Multi-access switchgear assembly

ABSTRACT

A metal clad switchgear assembly comprising multiple compartments defined within an electrical enclosure is provided. The compartments interchangeably accommodate electrical components, for example, current transformers, a circuit breaker, a control power transformer, an epoxy encapsulated potential transformer, etc., electrical cables, and bus bars in predetermined positions for allowing front access and/or rear access to them. One or more compartments are configured for enabling the electrical cables to enter into and/or exit out from the electrical enclosure for allowing front and/or rear access to the electrical cables. A mounting block assembly is positioned in one or more of the compartments for mounting, enclosing, and providing front access to the electrical components. One or more infrared windows and inspection windows are positioned on a front side and/or a rear side of the switchgear assembly for scanning and providing a visual indication of the electrical components, the electrical cables, and the bus bars.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application ofnon-provisional patent application Ser. No. 12/905,077 titled “FrontAccessible Switchgear Assembly”, filed on Oct. 14, 2010 in the UnitedStates Patent and Trademark Office, and claims the benefit ofprovisional patent application No. 61/352,022 titled “Multi-accessSwitchgear Assembly”, filed on Jun. 7, 2010 in the United States Patentand Trademark Office.

The specifications of the above referenced patent applications areincorporated herein by reference in their entirety.

BACKGROUND

The apparatus disclosed herein, in general, relates to electricalenclosures. More particularly, the apparatus disclosed herein relates toelectrical enclosures that provide, for example, front access only, andfront and rear access herein referred to a “multi-access”, to electricalbus members, multiple electrical components, and apparatuses housedwithin the electrical enclosures. Furthermore, the apparatus disclosedherein relates to electrical bus assemblies for electrical enclosuresand arc resistant electrical enclosures.

Medium voltage electrical components and apparatuses, for example,circuit breakers, potential transformers, current transformers, controlpower transformers, etc., are often housed in an electrical enclosurecalled a switchgear cabinet. The medium voltage electrical componentsand apparatuses operate, for example, in a range of about 1000 volts toabout 100,000 volts. The switchgear cabinet for medium voltage equipmenttypically occupies a large space and is difficult to access. As such,maintenance and space considerations are driving factors in the designof new electrical equipment. There is a need for constructing aswitchgear assembly that makes efficient use of the available floorspace and minimizes the time required for inspection, repair andmaintenance of equipment accommodated within the switchgear assembly.

Switchgear cabinets, particularly medium voltage metal clad switchgearcabinets are often damaged due to arcing. An explosion caused by arcingwithin a switchgear cabinet results in significant economic loss due tointerruption of energy distribution, and damage of the switchgearcabinet and the electrical components or equipment accommodated in theswitchgear cabinet. Consequently, maintenance personnel inspecting andservicing the switchgear cabinets have to wear protective gear that isbulky and expensive. Typical arc resistant switchgear cabinets tend tobe very large and often have heavy sheet metal enclosures. Suchconfigurations require significant space. Some switchgear cabinetsemploy an external arcing chamber that limits the configuration of theelectrical components, equipment, etc., within the switchgear cabinet.

Conventional switchgear cabinets typically provide only a single access,that is, a front access or a rear access to the electrical componentsand electrical cables within the switchgear cabinet, which placesrestrictions on the arrangement of the electrical components and theelectrical cables within the switchgear cabinet. Therefore, singleaccess switchgear cabinets do not make an efficient use of the availablefloor space owing to the lesser flexibility available in positioning theelectrical components and the electrical cables within the switchgearcabinet. Moreover, conventional single access switchgear cabinets do notallow accommodation of multiple electrical components along withelectrical cables in a single section. Hence, there is a need for aswitchgear cabinet that provides both front access and rear access tothe electrical components and the electrical cables for providingincreased flexibility in positioning of the electrical components andthe electrical cables within the switchgear cabinet, which results inefficient use of space and flexible accessibility. Moreover, there is aneed for a switchgear cabinet that enables accommodation of multipleelectrical components in a single section of the switchgear cabinet,thereby minimizing requirement of additional sections.

Furthermore, conventional switchgear cabinets utilize bar type currenttransformers that are mounted in the rear making it difficult to replacea transformer in the field if one of the transformers fail. Therefore,there is a need for mounting transformers and other electricalcomponents in the front of the switchgear cabinet for easieraccessibility for maintenance and inspection.

Moreover, there are significant limitations with respect to the size ofpotential transformers and control power transformers that are availablein conventional switchgear cabinets. For example, the maximum voltagefor a potential transformer in a conventional metal clad switchgearcabinet is about 5000V and the maximum power for a control powertransformer is about 5 kVA.

Conventional metal clad switchgear cabinets for the North Americanmarket need to meet stringent Institute of Electrical and ElectronicsEngineers (IEEE) requirements and American National Standards Institute(ANSI) requirements. These standards require a circuit breaker to betested inside the switchgear cabinets that have limited cooling andtherefore limiting the temperature rise within the switchgear cabinetbecomes a major challenge. Furthermore, as per InternationalElectrotechnical Commission (IEC) standards, barriers betweencompartments in the switchgear cabinets are not a requirement, thereforecooling the circuit breaker within the switchgear cabinet is mucheasier. IEC designed equipment, would have to be derated significantlyif no changes are made.

Furthermore, conventional metal clad switchgear cabinets pose additionalchallenges to meet ANSI and Underwriters Laboratories (UL) requirementsbecause of limited space and limited cooling. In addition, IEEE/ANSIdesigned equipment requires bus bars within the switchgear cabinet to beinsulated, making it more difficult to cool the critical currentcarrying bus bars in certain compartments of the switchgear cabinet thataccommodate the circuit breaker. Alternatively, expensive heat sinkshave to be employed to limit temperature rise. The addition of heatsinks is a difficult task in the compact space available and posessignificant challenges to pass the required lightning impulse test dueto space limitations and the shape of the heat sink.

Hence, there is a long felt but unresolved need for an arc resistantmetal clad switchgear assembly that has a compact footprint and provideseither front access only, or front access and rear access hereinreferred to as “multi-access” to electrical components, electricalcables, and equipment accommodated in the switchgear assembly forinspection, testing and maintenance with limited space requirements andwithout protective gear. Moreover, there is a need for a compactswitchgear assembly that allows increased flexibility in positioning ofthe electrical components and the electrical cables within theswitchgear assembly without limitations in configurations of theelectrical components, and that also enables accommodation of multipleelectrical components along with the electrical cables in a singlesection of the switchgear assembly. Furthermore, there is a need for acompact switchgear assembly that allows successful testing of theelectrical components, for example, circuit breakers that areaccommodated in the switchgear assembly without additional heat sinks.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described in the detailed descriptionof the invention. This summary is not intended to identify key oressential inventive concepts of the claimed subject matter, nor is itintended for determining the scope of the claimed subject matter.

The metal clad switchgear assembly disclosed herein addresses the abovestated need for a compact arc resistant metal clad switchgear assemblythat has a compact footprint and provides either front access only, orfront access and rear access herein referred to as “multi-access” toelectrical components, electrical cables, and equipment accommodated inthe switchgear assembly for inspection, testing and maintenance withlimited space requirements and without protective gear. The metal cladswitchgear assembly disclosed herein allows increased flexibility inpositioning of the electrical components and the electrical cableswithin the metal clad switchgear assembly without limitations inconfigurations of the electrical components, and also enablesaccommodation of multiple electrical components along with theelectrical cables in a single section of the metal clad switchgearassembly. Adjacent sections defined in an electrical enclosure of themetal clad switchgear assembly are separated by vertical metal barriersfor compartmentalizing active electrical components in the electricalenclosure. The “metal clad switchgear assembly” is herein referred to asa “switchgear assembly”.

The switchgear assembly disclosed herein allows access to the electricalcomponents, the electrical cables, equipment, etc., accommodated withinthe switchgear assembly from the front side only, or from the front sideand the rear side of the switchgear assembly. The switchgear assemblythat allows access to the electrical components, the electrical cables,the equipment, etc., accommodated within the switchgear assembly fromthe front side only is herein referred to as a “front accessibleswitchgear assembly”. The switchgear assembly that allows access to theelectrical components, the electrical cables, the equipment, etc.,accommodated within the switchgear assembly from the front side and/orthe rear side of the switchgear assembly is herein referred to as a“multi-access switchgear assembly”. The switchgear assembly disclosedherein allows successful testing of the electrical components, forexample, circuit breakers, that are accommodated in the switchgearassembly without additional heat sinks.

The switchgear assembly disclosed herein comprises multiple compartmentsdefined within an electrical enclosure, a mounting block assembly,multiple electrical components, electrical cables, and bus bars. Theelectrical enclosure is divided into, for example, a first section and asecond section. The compartments comprising, for example, uppercompartments, middle compartments, lower compartments, a centralcompartment, rear compartments, etc., are defined in the first sectionand the second section of the electrical enclosure. The compartments areconfigured to interchangeably accommodate one or more electricalcomponents, electrical cables, and bus bars. The electrical cablescomprise, for example, input electrical cables and output electricalcables. One or more of the compartments, for example, an uppercompartment, a front lower component, and/or a rear lower compartmentare configured for enabling the electrical cables to enter into and/orexit out from the electrical enclosure for allowing front access and/orrear access to the electrical cables. The electrical components and theelectrical cables are electrically connected in predetermined positionsin the compartments for allowing front access and/or rear access to theelectrical components, the electrical cables, and the bus bars withinthe electrical enclosure. One or more of the electrical components andthe electrical cables are in electrical communication with one or moreof the bus bars in one or more of the compartments. In an embodiment, alow voltage compartment is configured, for example, in one of the uppercompartments, the middle compartments, and/or the lower compartments,and isolated from the other compartments.

The switchgear assembly disclosed herein further comprises a plenumchamber rearwardly positioned in the electrical enclosure. The plenumchamber is in communication with one or more of the compartments withinthe electrical enclosure, for example, via an exhaust chamber. Theexhaust chamber is in adjacent communication with the plenum chamber.The plenum chamber provides an exit path for releasing pressure andgases generated by the electrical components and the electrical cablesaccommodated in the compartments during an event of arcing within theelectrical enclosure. The switchgear assembly disclosed herein furthercomprises flaps positioned between the compartments and the plenumchamber for preventing the gases and external particulate matter fromescaping the plenum chamber and entering into the compartments via theplenum chamber. The flaps isolate one or more of the compartments andthe plenum chamber in the electrical enclosure. One of the compartments,for example, an upper compartment, is configured as a low voltagecompartment for accommodating control equipment. In an embodiment, thelow voltage compartment is isolated from the plenum chamber and othercompartments, for example, the high voltage compartments in theswitchgear assembly.

The mounting block assembly of the switchgear assembly disclosed hereinis positioned in one or more of the compartments for mounting one ormore of the electrical components and for providing front access to themounted electrical components for inspection and maintenance. Eachmounting block assembly in the switchgear assembly comprises a basemounting block, multiple mounting legs, and a mounting block cover. Themounting legs extend frontwardly from the base mounting block formounting one or more of the electrical components and for allowing frontaccess to the mounted electrical components. The mounting block cover isremovably attached to the base mounting block for enclosing the mountedelectrical components on the mounting legs. The mounting block cover isremovable for providing front access to the mounted electricalcomponents for inspection and maintenance. The mounting block assemblyis configured to reduce temperature rise in the compartments.

The electrical components and the electrical cables are accommodated andelectrically connected in predetermined positions in the compartments ofthe switchgear assembly for allowing front access and/or rear access tothe electrical components, the electrical cables, the bus bars withinthe electrical enclosure for cable connections, and current transformersmounted on the mounting legs of the mounting block assembly. Theelectrical components are arranged in interchangeable configurations inthe compartments within the electrical enclosure. The electricalcomponents interchangeably accommodated in the compartments with theelectrical enclosure comprise, for example, a circuit breaker, a controlpower transformer having one of multiple power ratings (kVA), an epoxyencapsulated potential transformer having one of multiple voltage levels(kV), current transformers having one or more of multiple currentratios, etc. Each current transformer mounted on a mounting leg of onemounting block assembly has the same current ratio, for example, 1200:5.The current transformers mounted on a mounting leg of another mountingblock assembly in another section of the electrical enclosure may have adifferent current ratio, for example, 600:5 or 300:5.

In an embodiment, the circuit breaker is accommodated and electricallyconnected in the middle compartment defined, for example, in the firstsection of the electrical enclosure. The circuit breaker is electricallyconnected within the mounting block assembly. The circuit breakercontacts one or more of the bus bars via the mounting block assembly.The control power transformer is mounted and electrically connected inthe middle compartment defined, for example, in the second section ofthe electrical enclosure and communicates with the other electricalcomponents in the electrical enclosure via the mounting block assemblyand one or more of the bus bars. In an embodiment, the epoxyencapsulated potential transformer is mounted and electrically connectedin a middle compartment, or a lower compartment defined, for example, inthe first section or the second section of the electrical enclosure andcommunicates with the other electrical components in the electricalenclosure via the mounting block assembly and one or more of the busbars.

In an embodiment, the epoxy encapsulated potential transformer, theelectrical cables, and the circuit breaker or the control powertransformer are positioned in a single section of the switchgearassembly. For example, the epoxy encapsulated potential transformer canbe positioned in the front lower compartment, the electrical cables canbe positioned in the rear lower compartment, and the circuit breaker canbe positioned in the middle compartment defined in the first section ofthe electrical enclosure. In another example, the epoxy encapsulatedpotential transformer can be positioned in the front lower compartment,the electrical cables can be positioned in the rear lower compartment,and the control power transformer can be positioned in the middlecompartment defined in the second section of the electrical enclosure.

The switchgear assembly disclosed herein further comprises one or morefuse sleeve assemblies operably connected to each of the control powertransformer and the epoxy encapsulated potential transformer. The fusesleeve assemblies allow high voltage primary connections of the controlpower transformer and the epoxy encapsulated potential transformer inthe electrical enclosure. The fuse sleeve assemblies provide insulatingbarriers between the high voltage primary connections and the electricalenclosure. The fuse sleeve assemblies operably connected to each of thecontrol power transformer and the epoxy encapsulated potentialtransformer contact one or more of the bus bars, for example, in a rearcompartment within the electrical enclosure via the mounting blockassembly, thereby creating an ultra compact switchgear assembly. Thefuse sleeve assemblies contact a cylindrical bus mounted in the mountingblock assembly. The mounting block assembly is configured to accommodateeach of the fuse sleeve assemblies of the control power transformer andthe epoxy encapsulated potential transformer and to isolate phases ofthe control power transformer and the epoxy encapsulated potentialtransformer. The control power transformer and the epoxy encapsulatedpotential transformer comprise low voltage contacts configured todisengage from low voltage connections within the electrical enclosurefor preventing an event of arcing. In an embodiment, insulating barriersare provided between high voltage primary connections and the electricalenclosure of the switchgear assembly for preventing exposure of activeelectrical components within the electrical enclosure.

In an embodiment, the current transformer is mounted in the mountingblock assembly, for example, in a middle compartment within theelectrical enclosure and adapted for saving space in the electricalenclosure. In an embodiment, the current transformers are mounted on aninput and an output of the circuit breaker via the mounting blockassembly. In an embodiment, a cord is electrically connected to thecircuit breaker for low voltage connection within the electricalenclosure.

The input electrical cables and output electrical cables enter intoand/or exit out from the electrical enclosure, for example, via an uppercompartment, a front lower compartment, and/or a rear lower compartmentin the electrical enclosure. The electrical cables are alsointerchangeably accommodated in the compartments, for example, the uppercompartment, the front lower compartment, and/or the rear lowercompartment within the electrical enclosure. The input electrical cablesand the output electrical cables are accessible from the front sideand/or the rear side of the switchgear assembly. One or more of the busbars allow electrical communication between the electrical componentswithin the electrical enclosure. One or more of the bus bars alsoelectrically communicate with the electrical cables. The bus bars areelectrically connected in the rear compartments within the electricalenclosure. In an embodiment, the bus bars comprise horizontal bus barselectrically connected in the rear compartments within the electricalenclosure. One or more of the horizontal bus bars allow connection toadjacent sections defined in the electrical enclosure, connectionbetween one or more of the electrical components in the adjacentsections defined in the electrical enclosure, connection between theelectrical cables in adjacent compartments in the electrical enclosureand in the adjacent sections defined in the electrical enclosure, andconnection to one or more other switchgear assemblies. The multi-accessswitchgear assembly can be configured to line up with a switchgearhaving a current rating of, for example, about 2000 amperes, therebyenabling usage of circuit breakers having current ratings of, forexample, about 1200 amperes and 2000 amperes in a single line up.

The switchgear assembly disclosed herein further comprises one or moreinfrared windows positioned at predetermined locations on a front sideand/or a rear side of the switchgear assembly for front scanning and/orrear scanning of the electrical components, the electrical cables, andthe bus bars in the compartments for inspection and maintenance. In anembodiment, support brackets are connected to the infrared windows forprotecting the infrared windows from rupture. The switchgear assemblydisclosed herein further comprises one or more inspection windows, forexample, windows made of Lexan® of Saudi Basic Industries Corp,positioned at predetermined locations on the front side and/or the rearside of the switchgear assembly for providing a front visual indicationand/or a rear visual indication of the electrical components, theelectrical cables, and the bus bars for inspection and maintenance andfor critical electrical high voltage connections.

The switchgear assembly disclosed herein further comprises surgearresters positioned, for example, in a rear compartment within theelectrical enclosure. The surge arresters protect the electricalcomponents, the bus bars, the mounting block assembly, the inspectionwindows, the infrared windows, the input electrical cables, the outputelectrical cables, and the compartments defined with the electricalenclosure in an event of a lightning surge. The surge arresters areelectrically connected to one or more of the bus bars in the electricalenclosure via short high voltage electrical cables. The surge arrestersare compact and represent a unique way to mount and connect them to makethe switchgear assembly compact.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe invention, is better understood when read in conjunction with theappended drawings. For the purpose of illustrating the invention,exemplary constructions of the invention are shown in the drawings.However, the invention is not limited to the specific methods andinstrumentalities disclosed herein.

FIG. 1A exemplarily illustrates a cut-away left perspective view of afront accessible switchgear assembly.

FIG. 1B exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly, showing a circuit breakerelectrically connected in a middle compartment of the front accessibleswitchgear assembly.

FIG. 2 exemplarily illustrates a cut-away right perspective view of thefront accessible switchgear assembly.

FIG. 3 exemplarily illustrates a cut-away rear perspective view of thefront accessible switchgear assembly.

FIG. 4A exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly, showing surge arresters positionedin a rear compartment defined in a first section of an electricalenclosure of the front accessible switchgear assembly.

FIG. 4B exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly, showing support brackets forprotecting infrared windows positioned on a rear side of the frontaccessible switchgear assembly.

FIG. 5 exemplarily illustrates a cut-away right perspective view of thefront accessible switchgear assembly, showing a control powertransformer electrically connected in a middle compartment and an epoxyencapsulated potential transformer electrically connected in a lowercompartment of the front accessible switchgear assembly.

FIG. 6 exemplarily illustrates a left perspective view of the frontaccessible switchgear assembly.

FIG. 7 exemplarily illustrates a left orthogonal view of the frontaccessible switchgear assembly.

FIG. 8 exemplarily illustrates a front orthogonal view of the frontaccessible switchgear assembly, showing an infrared window andinspection windows positioned at predetermined locations on the frontside of the front accessible switchgear assembly.

FIG. 9 exemplarily illustrates a rear perspective view of the frontaccessible switchgear assembly, showing infrared windows and inspectionwindows positioned at predetermined locations on the rear side of thefront accessible switchgear assembly.

FIG. 10 exemplarily illustrates a bottom orthogonal view of the frontaccessible switchgear assembly, showing a front lower compartment of thefront accessible switchgear assembly configured for enabling electricalcables to enter into and/or exit out from the electrical enclosure.

FIG. 11A exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly, showing a circuit breakerelectrically connected in a middle compartment of the front accessibleswitchgear assembly.

FIG. 11B exemplarily illustrates a bottom orthogonal view of the frontaccessible switchgear assembly of FIG. 11A, showing the electricalcables entering into the electrical enclosure via the front lowercompartment defined in the first section of the electrical enclosure.

FIG. 12 exemplarily illustrates a cut-away right orthogonal view of thefront accessible switchgear assembly, showing a control powertransformer electrically connected in a middle compartment and an epoxyencapsulated potential transformer electrically connected in a lowercompartment of the front accessible switchgear assembly.

FIG. 13 exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly, showing the electrical cableselectrically connected to the upper horizontal bus bars via cableconnection bus bars.

FIGS. 14A-14B exemplarily illustrate cut-away left orthogonal views of asecond section of the front accessible switchgear assembly, showingelectrical connection of upper horizontal bus bars from a first sectionof the electrical enclosure to lower horizontal bus bars in the secondsection of the electrical enclosure via transitional bus bars.

FIG. 15 exemplarily illustrates a cut-away left orthogonal view of thefirst section of the front accessible switchgear assembly, showing theupper horizontal bus bars accommodated in a central compartment definedin the first section of the front accessible switchgear assembly andelectrically connected to the lower horizontal bus bars that extend intothe second section of the front accessible switchgear assembly, viamounting block assemblies with a mounted circuit breaker.

FIG. 16A exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly, showing an upper compartment ofthe front accessible switchgear assembly configured for enabling theelectrical cables to enter into and/or exit out from the electricalenclosure, where the electrical cables are electrically connected toupper horizontal bus bars via cable connection bus bars.

FIG. 16B exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly, showing an upper compartment ofthe front accessible switchgear assembly configured for enabling theelectrical cables to enter into and/or exit out from the electricalenclosure, and a support bracket for protecting an infrared windowpositioned on a front side of the front accessible switchgear assembly.

FIG. 16C exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly, showing an upper compartment ofthe front accessible switchgear assembly configured for enabling theelectrical cables to enter into and/or exit out from the electricalenclosure, where the electrical cables are electrically connected tolower horizontal bus bars via cable connection bus bars.

FIG. 16D exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly, showing an upper compartment ofthe front accessible switchgear assembly configured for enabling theelectrical cables to enter into and/or exit out from the electricalenclosure, and a support bracket for protecting an infrared windowpositioned on a front side of the front accessible switchgear assembly.

FIG. 17 exemplarily illustrates a cut-away left perspective view of amulti-access switchgear assembly, showing electrical cables accommodatedin a rear lower compartment, a circuit breaker accommodated in a middlecompartment, and an epoxy encapsulated potential transformeraccommodated in a front lower compartment, in a single section of themulti-access switchgear assembly.

FIG. 18A exemplarily illustrates a cut-away left perspective view of themulti-access switchgear assembly, showing electrical cables accommodatedin the rear lower compartment of the multi-access switchgear assemblyand electrically connected to the upper horizontal bus bars via thecable connection bus bars.

FIG. 18B exemplarily illustrates a bottom orthogonal view of themulti-access switchgear assembly of FIG. 18A, showing the electricalcables entering into the electrical enclosure via the rear lowercompartment of the multi-access switchgear assembly.

FIG. 19A exemplarily illustrates a cut-away left perspective view of themulti-access switchgear assembly, showing electrical cables accommodatedin a front lower compartment and the rear lower compartment of themulti-access switchgear assembly.

FIG. 19B exemplarily illustrates a bottom orthogonal view of themulti-access switchgear assembly of FIG. 19A, showing the electricalcables entering into the electrical enclosure via the front lowercompartment and the rear lower compartment of the multi-accessswitchgear assembly.

FIGS. 20A-20C exemplarily illustrate perspective views of a mountingblock assembly for the front accessible switchgear assembly and themulti-access switchgear assembly.

FIGS. 21A-21B exemplarily illustrate perspective views of a circuitbreaker utilized in the front accessible switchgear assembly and themulti-access switchgear assembly, showing tulip contacts of the circuitbreaker.

FIG. 21C exemplarily illustrates a plan view showing connection of thecircuit breaker within the mounting block assembly.

FIG. 21D exemplarily illustrates a sectional view taken at section A-Aof FIG. 21C, showing connection of a tulip contact of the circuitbreaker to a cylindrical bus that runs inside the mounting blockassembly.

FIGS. 22A-22B exemplarily illustrate perspective views of a controlpower transformer comprising fuse sleeve assemblies utilized in thefront accessible switchgear assembly and the multi-access switchgearassembly.

FIG. 22C exemplarily illustrates a perspective view of the control powertransformer, showing an exploded view of one of the fuse sleeveassemblies operably connected to the control power transformer.

FIG. 22D exemplarily illustrates a plan view showing connection of thecontrol power transformer to the mounting block assembly.

FIG. 22E exemplarily illustrates a sectional view taken at section B-Bof FIG. 22D, showing connection of the control power transformer to acylindrical bus that runs inside the mounting block assembly.

FIGS. 23A-23B exemplarily illustrate perspective views of an epoxyencapsulated potential transformer utilized in the front accessibleswitchgear assembly and the multi-access switchgear assembly.

FIG. 23C exemplarily illustrates a perspective view of the epoxyencapsulated potential transformer, showing an exploded view of one ofthe fuse sleeve assemblies operably connected to the epoxy encapsulatedpotential transformer.

FIG. 23D exemplarily illustrates a plan view showing connection of theepoxy encapsulated potential transformer to the mounting block assembly.

FIG. 23E exemplarily illustrates a sectional view taken at section C-Cof FIG. 23D, showing connection of the epoxy encapsulated potentialtransformer to a cylindrical bus that runs inside the mounting blockassembly.

FIG. 24 illustrates a method for constructing a front accessibleswitchgear assembly.

FIG. 25 illustrates a method for constructing a multi-access switchgearassembly.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is a compact arc resistant metal clad switchgearassembly that has a compact footprint and provides either front accessonly, or front access and rear access herein referred to as“multi-access”, to electrical components, electrical cables, equipment,etc., accommodated in the switchgear assembly for inspection, testingand maintenance with limited space requirements and without protectivegear. The compact arc resistant metal clad switchgear assembly thatprovides front access only is herein referred to as a “front accessibleswitchgear assembly”. As used herein, the front accessible switchgearassembly 100, exemplarily illustrated in FIGS. 1A-16D, refers to aswitchgear assembly 100 that allows access to electrical cables 111,electrical components 113, 118, 119, 120, etc., the bus bars 103, andequipment accommodated within the switchgear assembly 100 from the frontside 100 a of the switchgear assembly 100 only. The compact arcresistant metal clad switchgear assembly that provides front accessand/or rear access, that is, multi-access, is herein referred to as a“multi-access switchgear assembly”. As used herein, the multi-accessswitchgear assembly 1700, exemplarily illustrated in FIGS. 17-19B,refers to a switchgear assembly 1700 that allows access to theelectrical cables 111, the electrical components 113, 118, 119, 120,etc., the bus bars 103, and equipment accommodated within the switchgearassembly 1700 from the front side 1700 a and/or the rear side 1700 b ofthe switchgear assembly 1700. As used herein, the electrical cables 111comprise incoming electrical cables and outgoing electrical cables.

FIGS. 1A-1B exemplarily illustrate cut-away left perspective views of afront accessible switchgear assembly 100. The front accessibleswitchgear assembly 100 disclosed herein comprises a compact and arcresistant electrical enclosure 101, multiple compartments 102 definedwithin the electrical enclosure 101, one or more mounting blockassemblies 104, a plenum chamber 105, electrical cables 111, electricalcomponents 113, 118, 119, 120, etc., and bus bars 103. The frontaccessible switchgear assembly 100 disclosed herein is a metal cladswitchgear assembly. Adjacent sections 101 a and 101 b defined in theelectrical enclosure 101 of the front accessible metal clad switchgearassembly 100 are separated by vertical metal barriers 101 c forcompartmentalizing active electrical components 118, 119, 120, etc., inthe electrical enclosure 101. The front accessible metal clad switchgearassembly 100 has a higher duty cycle and a greater number of loadoperations, for example, about 10 times to about 1000 times greaternumber of load operations than that of a metal enclosed switchgearassembly. The “front accessible metal clad switchgear assembly” isherein referred to as a “front accessible switchgear assembly”.

The size of the front accessible switchgear assembly 100 disclosedherein is configured to ensure space savings and easy access from thefront side 100 a of the front accessible switchgear assembly 100. Thefront accessible switchgear assembly 100 disclosed herein refers to a15000 volts (V) switchgear assembly and can be extended to higher andlower voltages. The front accessible switchgear assembly 100 disclosedherein accommodates 15 kilovolt (kV) class equipment and providessolutions for 95 kV lightning impulse voltage and 1200 ampere (A) ratingwith a control power transformer 119, exemplarily illustrated in FIG. 2,rated up to 15 kVA. The front accessible switchgear assembly 100disclosed herein can be extended to higher ratings and can be used forlow voltage switchgear assemblies rated 600V and below.

The compartments 102 are configured to interchangeably accommodate oneor more electrical components, for example, a control power transformer119 having one of multiple power ratings (kVA), one or more currenttransformers 113 having one or more of multiple current ratios, acircuit breaker 118, an epoxy encapsulated potential transformer 120having one of multiple voltage levels (kV), etc., input and outputelectrical cables 111 herein referred to as “electrical cables”, and busbars 103, for example, upper horizontal bus bars 103 a, lower horizontalbus bars 103 d exemplarily illustrated in FIG. 2, cable connection busbars 103 c, etc.

The electrical enclosure 101 of the front accessible switchgear assembly100 exemplarily illustrated in FIGS. 1A-1B, FIGS. 2-6, and FIGS. 8-10 isdivided into two sections, for example, a first section 101 a and asecond section 101 b. The front accessible switchgear assembly 100disclosed herein is a compact basic two section switchgear assembly 100.For front accessibility in the front accessible switchgear assembly 100,each of the sections 101 a and 101 b of the electrical enclosure 101 isconfigured, for example, 23.62 inches wide, 60 inches deep, and 96inches high to provide all basic functions and components needed in thefront accessible switchgear assembly 100. For front and rearaccessibility in the multi-access switchgear assembly 1700 exemplarilyillustrated in FIG. 17, FIG. 18A, and FIG. 19A, each of the sections 101a and 101 b of the electrical enclosure 101 is configured, for example,23.62 inches wide, 72 inches deep, and 96 inches high to provide allbasic functions and components needed in the multi-access switchgearassembly 1700. The increased depth of the multi-access switchgearassembly 1700 enables accommodation of electrical equipment, forexample, circuit breakers 118 with high current ratings ranging from1200 A to about 2000 A. Moreover, the multi-access switchgear assembly1700 with its larger volume can accommodate two circuit breakers 118with different current ratings, for example, a first circuit breaker 118with a current rating of 1200 A and a second circuit breaker 118 with acurrent rating of 2000 A.

The compartments 102 comprising, for example, upper compartments 102 a,middle compartments 102 b, lower compartments 102 c, a centralcompartment 102 d, rear compartments 102 e, etc., are defined in thefirst section 101 a and the second section 101 b of the electricalenclosure 101. For example, the first section 101 a of the electricalenclosure 101 defines one of the upper low voltage compartments 107, oneof the middle compartments 102 b, one of the lower compartments 102 c,the central compartment 102 d, and one of the rear compartments 102 e.

The first section 101 a of the electrical enclosure 101 alsoaccommodates the plenum chamber 105. The plenum chamber 105 isrearwardly positioned in the electrical enclosure 101. The plenumchamber 105 is an open space for hot gases to escape from the electricalenclosure 101 to the outside environment, for example, via a ventingduct system of a building. The plenum chamber 105 comprises a flange 105a that provides an exit path for the gases to escape. The flange 105 ais connected to the venting duct system for exhausting the gases. Theflange 105 a is configured as a perforated plate, a thin sheet metalplate, or an aluminum plate with flaps, which prevents the entry ofgases, external particulate matter, etc., into the electrical enclosure101 from the venting duct system of the building. The plenum chamber 105provides a large space for hot gases to expand and allows safe exhaustof, for example, arcs, in an event of arcing. The safe exhaust of hotgases and arcs ensure safety of personnel working around the electricalenclosure 101 of the front accessible switchgear assembly 100. Theplenum chamber 105 is made of the same material, for example, sheetmetal, as the compartments 102. The plenum chamber 105 is incommunication with one or more of the compartments 102 and provides anexit path for releasing pressure and gases generated by the electricalcables 111 and the electrical components 113, 118, 119, 120, etc.,accommodated in the compartments 102 during an event of arcing withinthe electrical enclosure 101.

The plenum chamber 105 communicates with one or more of the compartments102 via an exhaust chamber 112 in adjacent communication with the plenumchamber 105. The exhaust chamber 112 extends from the first section 101a through to the second section 101 b of the electrical enclosure 101.The plenum chamber 105 is rearwardly positioned to connect to ventingducts of a building to exhaust the gases to the outside environmentsafely during an arcing event. The plenum chamber 105 may be positionedto the left or the right of the front accessible switchgear assembly 100and may be connected to the venting ducts that go in an upward directionor a downward direction based on typical design practices.

The front accessible switchgear assembly 100 efficiently exhausts thegases and the pressure from the compartments 102 to the plenum chamber105 during an arcing event without creating excessive pressure in thecompartments 102. The compartments 102 of the front accessibleswitchgear assembly 100 are configured to minimize the pressure of gasesduring an arcing event. The front accessible switchgear assembly 100disclosed herein further comprises flaps 106 a, 106 b, and 106 cpositioned between one or more of the compartments 102 and the plenumchamber 105 for preventing the gases, external particulate matter, andother external elements from entering the compartments 102 via theplenum chamber 105. The flaps 106 a, 106 b, and 106 c are configured asperforated plates for allowing gases to exit into the plenum chamber105. For example, the flaps 106 a are positioned at the top of thecentral compartment 102 d defined in the first section 101 a of theelectrical enclosure 101, and at the top of the rear compartment 102 edefined in the second section 101 b of the electrical enclosure 101.Furthermore, the flaps 106 b and 106 c are provided for the exhaustchamber 112 and the middle compartment 102 b respectively as exemplarilyillustrated in FIG. 1A. The flaps 106 a and 106 b delineate the exhaustchamber 112 within the electrical enclosure 101.

The flaps 106 a, 106 b, and 106 c are made of a thin metal or aluminumand if there is an arcing event and the pressure of gases in thecompartments, for example, 102 b, 102 c, and 102 d becomes high, one ormore of the flaps 106 a, 106 b, and 106 c open to allow the gases toexhaust to the plenum chamber 105. For example, if there is an arcingevent in the central compartment 102 d, the gases exit to the plenumchamber 105 through one or more of the flaps 106 a. In the event ofarcing in the lower compartment 102 c defined in the first section 101 aof the electrical enclosure 101 that accommodates the electrical cables111 exemplarily illustrated in FIG. 1A, gases from the lower compartment102 c exit, for example, through the rear compartment 102 e and into theplenum chamber 105 via one of the flaps 106 a. If an electricalcomponent, for example, an epoxy encapsulated potential transformer 120is positioned in the lower compartment 102 c defined in the secondsection 101 b of the electrical enclosure 101 as exemplarily illustratedin FIG. 2, the gases exit, for example, through the flap 106 cexemplarily illustrated in FIG. 1A, FIG. 16B, and FIG. 16D and into theplenum chamber 105, for example, via the flap 106 b of the exhaustchamber 112. In the event of arcing in the middle compartment 102 b, thegases exit from the middle compartment 102 b to the exhaust chamber 112,for example, via the flap 106 b and thereafter to the plenum chamber105.

One or more of the compartments 102, for example, the upper compartments102 a are configured as low voltage compartments 107 for accommodatingcontrol equipment (not shown). In an embodiment, the middle compartments102 b and the lower compartments 102 c can be configured as low voltagecompartments 107. The control equipment in the low voltage compartment107 is employed for relay and protection and comprises relay equipment,for example, overcurrent relays, differential relays, under voltagerelays, ground fault relays, protection relays, under frequency relays,integrated digital relays such as Schweitzer relays and Bassler relays,etc. The control equipment in the low voltage compartment 107 furthercomprises programmable logic controllers for performing controlfunctions, human machine interfaces for performing display functions,metering equipment for measurement and display of voltage, current,frequency, etc., and other control equipment for motor control, etc. Thecontrol equipment provides protection against current and voltagefluctuations, for example, over current, undercurrent, differentialvoltages, ground fault, etc. The control equipment provides protectionagainst changes in frequency, for example, under frequency, etc.

Control switches and push buttons are also provided on the low voltagecompartment 107. In an embodiment, control functions of the circuitbreaker 118 can be incorporated in the low voltage compartment 107. Acord 118 a configured, for example, as an umbilical cord, iselectrically connected to the circuit breaker 118 for low voltageconnection within the electrical enclosure 101. The cord 118 a makes thelow voltage connection via a connector 118 b, for example, a maleconnector as exemplarily illustrated in FIGS. 21A-21B. The outputs ofthe electrical components, for example, the current transformer 113, theepoxy encapsulated potential transformer 120, and the control powertransformer 119 can also be integrated in the low voltage compartment107 for control, protection and display functions. The control equipmentin the low voltage compartment 107 communicates with other controlequipment in the front accessible switchgear assembly 100 or otherexternal control equipment, for example, by communication protocols suchas Ethernet, Modbus, serial link, etc.

The low voltage compartment 107 is isolated from the plenum chamber 105and the other compartments 102 defined in the electrical enclosure 101.In an embodiment, the low voltage compartment 107 can be configured inthe upper compartment 102 a and isolated from the middle compartment 102b, the lower compartment 102 c, and the rear compartment 102 e. Inanother embodiment, the low voltage compartment 107 can be configured asa complete section comprising the upper compartment 102 a, the middlecompartment 102 b, and the lower compartment 102 c defined in the firstsection 101 a of the electrical enclosure 101 and is isolated from thehigh voltage rear compartments 102 e, for example, by sheet metalbarriers. In this embodiment, the low voltage compartment 107 is a fullsection extending from the upper compartment 102 a to the lowercompartment 102 c and encompassing the middle compartment 102 b. If thelow voltage compartment 107 is configured as a complete section and usedfor control, the electrical cables 111, the electrical components 113,118, 119, 120, etc., and the bus bars 103 are separated by metalbarriers. High voltage electrical components positioned in the centralcompartment 102 d and the rear compartment 102 e are isolated from thelow voltage compartment 107, for example, by sheet metal barriers.

The upper low voltage compartment 107 is isolated from the plenumchamber 105 and there is no communication between the upper low voltagecompartment 107 and the plenum chamber 105. By sealing the upper lowvoltage compartment 107 from the other high voltage compartments 102 b,102 c, 102 d, and 102 e and the plenum chamber 105, arc rating can beobtained for the front accessible switchgear assembly 100, where it ispossible to open the upper low voltage compartment 107 when the frontaccessible switchgear assembly 100 is energized, without protectiveclothing for maintenance of low voltage control circuits. This isapplied in, for example, a data center, health care, and other criticalfacilities. Significant arcing does not happen in the upper low voltagecompartment 107 since the available power is very low. The configurationand functioning of the compartments 102, the low voltage compartment107, the plenum chamber 105, the exhaust chamber 112, and the flaps 106a, 106 b, and 106 c of the front accessible switchgear assembly 100exemplarily illustrated in FIGS. 1A-16D also apply to the multi-accessswitchgear assembly 1700 exemplarily illustrated in FIGS. 17-19B.

The electrical cables 111 and the electrical components 113, 118, 119,120, etc., are electrically connected in predetermined positions in thecompartments 102 for allowing front access and/or rear access to theelectrical cables 111, the electrical components 113, 118, 119, 120,etc., and the bus bars 103 within the electrical enclosure 101. In thefront accessible switchgear assembly 100 as exemplarily illustrated inFIGS. 1A-16D, the electrical cables 111 and the electrical components113, 118, 119, 120, etc., are accessible only from the front side 100 aof the front accessible switchgear assembly 100. One or more of theelectrical cables 111 and the electrical components 113, 118, 119, 120,etc., are in electrical communication with one or more of the bus bars103 in one or more of the compartments 102. The bus bars 103 areelectrically connected in the rear compartments 102 e defined in thefirst section 101 a and the second section 101 b of the electricalenclosure 101. The configuration and functioning of the electricalcomponents 113, 118, 119, 120, etc., and the bus bars 103 of the frontaccessible switchgear assembly 100 exemplarily illustrated in FIGS.1A-16D also apply to the multi-access switchgear assembly 1700exemplarily illustrated in FIGS. 17-19B. In the multi-access switchgearassembly 1700 exemplarily illustrated in FIGS. 17-19B, the electricalcomponents 113, 118, 119, 120, etc., are accessible from the front side1700 a of the multi-access switchgear assembly 1700, while theelectrical cables 111 and one or more of the bus bars 103 are accessiblefrom the front side 1700 a and/or the rear side 1700 b of themulti-access switchgear assembly 1700 as exemplarily illustrated inFIGS. 17-19B.

The mounting block assembly 104 utilized in the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700 ispositioned in one or more of the compartments 102, for example, themiddle compartments 102 b, the central compartment 102 d, etc., definedin the electrical enclosure 101. The mounting block assembly 104 formounting one or more of the electrical components, for example, thecurrent transformers 113, the circuit breaker 118, etc., is disclosed inthe detailed description of FIGS. 20A-20C. The mounting block assembly104 provides front access to the mounted electrical components 113, 118,119, 120, etc., for inspection and maintenance. In an embodiment, themounting block assembly 104 is configured as a two-part assembly toincrease creepage distance resulting in a compact front accessibleswitchgear assembly 100 and a compact multi-access switchgear assembly1700.

One of the electrical components, for example, the circuit breaker 118is electrically connected in the middle compartment 102 b defined in thefirst section 101 a of the electrical enclosure 101 as exemplarilyillustrated in FIG. 1B. The construction of the circuit breaker 118 isdisclosed in the detailed description of FIGS. 21A-21B. The circuitbreaker 118 comprises tulip contacts 118 f provided on arms 118 cextending outwardly from the circuit breaker 118 as exemplarilyillustrated in FIGS. 21A-21B. The tulip contacts 118 f of the circuitbreaker 118 connect to a cylindrical bus 104 c made of, for example,copper, that runs inside the mounting block assembly 104 as exemplarilyillustrated in FIG. 21D, in the middle compartment 102 b defined in thefirst section 101 a of the electrical enclosure 101.

As exemplarily illustrated in FIGS. 1A-1B, FIG. 3, FIGS. 4A-4B, FIG. 10,FIGS. 11A-11B, FIG. 13, and FIGS. 16A-16D, one or more of thecompartments 102 a, 102 c, etc., defined in the first section 101 a ofthe electrical enclosure 101 are configured for enabling the electricalcables 111 to enter into and/or exit out from the electrical enclosure101 for allowing only front access to the electrical cables 111. In anembodiment, the electrical cables 111 are accommodated in a front lowercompartment 102 c defined in the second section 101 b of the electricalenclosure 101. The front accessible switchgear assembly 100 enables theaccommodation and electrical connection of the electrical cables 111 ina single compartment, for example, the front lower compartment 102 cdefined in the first section 101 a of the electrical enclosure 101. Theability to accommodate three phases of the electrical cables 111 in asingle compartment, for example, the front lower compartment 102 cprovides an ultra compact set up for the circuit breaker 118 as part ofthe front accessible switchgear assembly 100, thereby minimizing therequirement of additional sections or compartments 102.

The front accessible switchgear assembly 100 disclosed herein furthercomprises multiple surge arresters 116, for example, typically one foreach phase of the circuit of the front accessible switchgear assembly100. The surge arresters 116 are positioned, for example, in the rearcompartments 102 e defined in the electrical enclosure 101 forprotecting the electrical components 113, 118, 119, 120, etc., the busbars 103, inspection windows 109, infrared windows 108, the electricalcables 111, the mounting block assembly 104, the compartments 102defined within the electrical enclosure 101, etc., in an event of alightning surge. As exemplarily illustrated in FIGS. 1A-1B, FIGS. 3-5,and FIG. 11A, the surge arresters 116 are positioned in a rear lowercompartment 102 e defined in the first section 101 a of the electricalenclosure 101. The surge arresters 116 protect the electrical cables111, the electrical components 113, 118, 119, 120, etc., the bus bars103, the mounting block assembly 104, the compartments 102, etc., fromdamaging voltages generated during a lightning surge.

The surge arresters 116 are electrically connected to one or more of thebus bars 103, for example, the cable connection bus bars 103 c in theelectrical enclosure 101 via short high voltage electrical cables 110.The short high voltage electrical cables 110 provide, for example, alower electrical inductance that limits clamping voltage of the surgearresters 116 more effectively within the electrical enclosure 101,thereby increasing the effectiveness of the surge arresters 116. Theclamping voltage is the maximum amount of voltage that a surge arrester116 allows through it before the surge arrester 116 suppresses a powersurge. The surge arresters 116 suppress the power surge by diverting thepower to ground or by absorbing the excess energy. In an embodiment, thebase of the surge arresters 116 is grounded to the electrical enclosure101, for example, by creating metal to metal contact by making themounting surface free of paint. In another embodiment, a cable (notshown) can be used to make the grounding connection to the surgearresters 116. The surge arresters 116 are compact and are mounted andconnected within the electrical enclosure 101 to make the frontaccessible switchgear assembly 100 disclosed herein compact.

The bus bars 103 comprising, for example, upper horizontal bus bars 103a are electrically connected in the rear compartment 102 e defined inthe first section 101 a of the electrical enclosure 101. The bus bars103 are strips of conducting materials, for example, copper, aluminum,etc., that conduct electricity within the front accessible switchgearassembly 100. One or more of the horizontal bus bars 103 a and 103 dexemplarily illustrated in FIGS. 1A-1B and FIG. 2, allow connection toadjacent sections 101 a and 101 b defined in the electrical enclosure101, connection between the electrical components 119, 120, etc., in theadjacent sections 101 a and 101 b defined in the electrical enclosure101, connection between the electrical cables 111 in adjacentcompartments 102 in the electrical enclosure 101 and in the adjacentsections 101 a and 101 b defined in the electrical enclosure 101, andconnection to one or more other switchgear assemblies. The secondsection 101 b of the electrical enclosure 101 is exemplarily illustratedin FIG. 2.

The control power transformer 119 and the epoxy encapsulated potentialtransformer 120 are electrically connected to the cylindrical bus 104 cthat runs inside the mounting block assembly 104, for example, via thefuse sleeve assemblies 119 a and 120 a of the control power transformer119 and the epoxy encapsulated potential transformer 120 respectively asexemplarily illustrated in FIG. 22E and FIG. 23E respectively. The fusesleeve assemblies 119 a and 120 a of the control power transformer 119and the epoxy encapsulated potential transformer 120 respectivelycontact one or more of the bus bars 103 in the rear compartment 102 ewithin the electrical enclosure 101 via the cylindrical bus 104 c in themounting block assembly 104 and high voltage electrical cables (notshown). The mounting block assembly 104 is configured to accommodateeach of the fuse sleeve assemblies 119 a and 120 a of the control powertransformer 119 and the epoxy encapsulated potential transformer 120respectively and to isolate phases of the control power transformer 119and the epoxy encapsulated potential transformer 120 respectively.

The front accessible switchgear assembly 100 disclosed herein furthercomprises one or more infrared windows 108 and inspection windows 109positioned at predetermined locations on the front side 100 a and/or therear side 100 b of the front accessible switchgear assembly 100, asexemplarily illustrated in FIGS. 1A-1B and FIG. 4B, for inspection andmaintenance. The infrared windows 108 and the inspection windows 109 aredisclosed in the detailed description of FIG. 4B and FIG. 8. The frontaccessible switchgear assembly 100 disclosed herein further comprisescable bushings 117 positioned in the rear compartment 102 e andconfigured on a barrier 101 c between the adjacent sections 101 a and101 b of the electrical enclosure 101. The cable bushings 117 areprovided for receiving cables that connect the electrical components119, 120, etc., positioned in one adjacent section 101 b of theelectrical enclosure 101 to the bus bars 103 positioned in the otheradjacent section 101 a of the electrical enclosure 101. For example, thecable bushings 117 receive cables that connect the control powertransformer 119 and the epoxy encapsulated potential transformer 120 inthe second section 101 b of the electrical enclosure 101 to thehorizontal bus bars 103 a or the cable connection bus bars 103 c in thefirst section 101 a of the electrical enclosure 101.

The front accessible switchgear assembly 100 is compact and isconfigured with a depth of, for example, about 60 inches for frontaccess only. The width and height of each of the sections 101 a and 101b of the electrical enclosure 101 of the front accessible switchgearassembly 100 are, for example, about 23.62 inches and about 96 inchesrespectively. A front working clearance of, for example, about five feetis required for the front accessible switchgear assembly 100. In thecase of the front accessible switchgear assembly 100, no workingclearance is required in the rear and therefore the front accessibleswitchgear assembly 100 is effectively utilized for installations withlimited spaces.

The electrical cables 111 may be connected in the lower compartment 102c. The circuit breaker 118 and the control power transformer 119 aremounted in the middle compartment 102 b in the adjacent sections 101 aand 101 b of the electrical enclosure 101 respectively. The epoxyencapsulated potential transformer 120 may be mounted in the lowercompartment 102 c or in the middle compartment 102 b. In an embodimentas exemplarily illustrated in FIG. 3, the electrical cables 111 areconnected in the front lower compartment 102 c of the first section 101a, while the epoxy encapsulated potential transformer 120 is mounted inthe lower compartment 102 c of the second section 101 b of theelectrical enclosure 101.

The different compartments 102 that accommodate, for example, the epoxyencapsulated potential transformer 120, the control power transformer119, the circuit breaker 118, the electrical cables 111, etc., can beinterlocked using mechanical Kirk® keys of the Kirk Key InterlockCompany or may be interlocked electrically so that the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700are safe from a maintenance and user standpoint using standard schemes.

FIG. 2 exemplarily illustrates a cut-away right perspective view of thefront accessible switchgear assembly 100. FIG. 2 illustrates the secondsection 101 b of the electrical enclosure 101. The second section 101 bof the electrical enclosure 101 defines, for example, one of the upperlow voltage compartments 107, one of the middle compartments 102 b, oneof the lower compartments 102 c, one of the rear compartments 102 e, andthe exhaust chamber 112 extending from the first section 101 a throughto the second section 101 b of the electrical enclosure 101. The upperlow voltage compartment 107 accommodates the control equipment and isisolated from the middle compartments 102 b, the lower compartments 102c, the central compartment 102 d, and the rear compartments 102 e.

The compartments 102 interchangeably accommodate one or more of theelectrical components 118, 119, 120, etc. For example, the middlecompartment 102 b defined in the second section 101 b of the electricalenclosure 101 accommodates the control power transformer 119. Thecontrol power transformer 119 is electrically connected in the middlecompartment 102 b via the mounting block assembly 104 as exemplarilyillustrated in FIG. 2. The fuse sleeve assemblies 119 a of the controlpower transformer 119 contact one or more of the bus bars 103 in therear compartment 102 e within the electrical enclosure 101, for example,via the mounting block assembly 104 and high voltage electrical cables(not shown). The construction of the control power transformer 119 isdisclosed in the detailed description of FIGS. 22A-22C. The lowercompartment 102 c defined in the second section 101 b of the electricalenclosure 101 accommodates the epoxy encapsulated potential transformer120. The epoxy encapsulated potential transformer 120 is electricallyconnected in the lower compartment 102 c as exemplarily illustrated inFIG. 2. In an embodiment, the epoxy encapsulated potential transformer120 is electrically connected in the middle compartment 102 b defined inthe second section 101 b of the electrical enclosure 101. Theconstruction of the epoxy encapsulated potential transformer 120 isdisclosed in the detailed description of FIGS. 23A-23C. Mounting andelectrically connecting the epoxy encapsulated potential transformer 120in either the lower compartment 102 c or the middle compartment 102 bdefined in the second section 101 b of the electrical enclosure 101enables creation of an ultra low footprint front accessible switchgearassembly 100 and an ultra low footprint multi-access switchgear assembly1700. The fuse sleeve assemblies 120 a of the epoxy encapsulatedpotential transformer 120 contact one or more of the bus bars 103 in therear compartment 102 e within the electrical enclosure 101, for example,via the mounting block assembly 104 and high voltage electrical cables(not shown).

The bus bars 103 comprising, for example, the upper horizontal bus bars103 a and lower horizontal bus bars 103 d are electrically connected inthe rear compartment 102 e defined in the second section 101 b of theelectrical enclosure 101. The lower horizontal bus bars 103 d allowconnection to one or more other switchgear assemblies. The upperhorizontal bus bars 103 a are electrically connected to the lowerhorizontal bus bars 103 d via transitional bus bars 103 b disposed inthe second section 101 b of the electrical enclosure 101.

FIG. 3 exemplarily illustrates a cut-away rear perspective view of thefront accessible switchgear assembly 100. FIG. 3 illustrates theconnection of the cable connection bus bars 103 c from the mountingblock assembly 104 to the electrical cables 111 accommodated in thelower compartment 102 c defined in the first section 101 a of theelectrical enclosure 101. The cable connection bus bars 103 c arestaggered for ease of electrical connection to the electrical cables 111accommodated in the lower compartment 102 c defined in the first section101 a of the electrical enclosure 101. FIG. 3 also illustrates the busbars 103 electrically connected in the second section 101 b of theelectrical enclosure 101. The lower horizontal bus bars 103 d extendoutwardly from the rear compartment 102 e defined in the second section101 b of the electrical enclosure 101 for allowing connection to one ormore other switchgear assemblies.

The compartments 102 defined in the first section 101 a and the secondsection 101 b of the electrical enclosure 101 are separated by barriers101 c made of, for example, sheet metal. The components of the basic twosection front accessible switchgear assembly 100 may be combined to forma long switchgear assembly line up. For example, the bus bars 103, forexample, the upper horizontal bus bars 103 a and the lower horizontalbus bars 103 d allow connection of multiple switchgear assemblies toform a long switchgear assembly line up as the horizontal bus bars 103 aand 103 d line up either at the upper part or the lower part of the rearcompartments 102 e defined in the first section 101 a and the secondsection 101 b of the electrical enclosure 101. The two section frontaccessible switchgear assembly 100 is flexibly configured to adapt toany switchgear assembly line up in multiple applications. The upperhorizontal bus bars 103 a and the lower horizontal bus bars 103 d gothrough window bushings 114 and rest on the window bushings 114 so thatit is easy to make connections since the weight of the horizontal busbars 103 a and 103 d is carried by the window bushings 114. Smallsections of, for example, epoxy coated bus bars, insulated bus bars withRaychem, or any other suitable insulation, etc., can easily join thehorizontal bus bars 103 a and 103 d from two adjacent sections of theswitchgear assemblies. Ground bus bars (not shown) in the lowercompartment 102 c may also be connected on the front side 100 a of thefront accessible switchgear assembly 100 using, for example, smallcopper bus bars. The configuration and functioning of the bus bars 103of the front accessible switchgear assembly 100 exemplarily illustratedin FIGS. 1A-16D also apply to the multi-access switchgear assembly 1700exemplarily illustrated in FIGS. 17-19B.

In an embodiment, the front accessible switchgear assembly 100 furthercomprises insulating boots 123 that provide additional insulation whichincreases creepage distance and helps in withstanding lightning impulsesover time as insulators degrade. The insulating boots 123 are flexibleboot like covers that enclose exposed bus bars 103 in the frontaccessible switchgear assembly 100. The insulating boots 123 thereforehelp maintain long-term reliability of the front accessible switchgearassembly 100. The configuration and functioning of the insulating boots123 of the front accessible switchgear assembly 100 also apply to themulti-access switchgear assembly 1700 as disclosed in the detaileddescription of FIG. 17.

FIG. 4A exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly 100, showing surge arresters 116positioned in a rear compartment 102 e defined in the first section 101a of the electrical enclosure 101 of the front accessible switchgearassembly 100. The surge arresters 116 are electrically connected to thebus bars 103, for example, the cable connection bus bars 103 c in theelectrical enclosure 101 via short high voltage electrical cables 110.The circuit breaker 118 is electrically connected in the middlecompartment 102 b defined in the first section 101 a of the electricalenclosure 101. A cord 118 a is electrically connected to the circuitbreaker 118 for low voltage connection within the electrical enclosure101. For example, the cord 118 a electrically connects the circuitbreaker 118 to the control equipment in the upper low voltagecompartment 107 defined in the first section 101 a of the electricalenclosure 101. The low voltage connection comprises electricalconnection of a controller to the circuit breaker 118 for communicatingopen/close command signals to the circuit breaker 118, connection ofauxiliary contacts that indicate open/close status of the circuitbreaker 118, breaker interlocks that prevent closing of the circuitbreaker 118 if the circuit breaker 118 is not fully racked into themiddle compartment 102 b, connections to breaker under voltage relaysand other associated breaker auxiliary components, etc.

FIG. 4A also illustrates the lower horizontal bus bars 103 d extendingoutwardly from the rear compartment 102 e defined in the second section101 b of the electrical enclosure 101 for allowing connection to one ormore other switchgear assemblies. In an embodiment, support brackets 121protect the inspection windows 109 positioned on the front side 100 a ofthe front accessible switchgear assembly 100 from rupture. A supportbracket 121 protecting an inspection window 109 and an infrared window108 on the front side 100 a and/or the rear side 100 b of the frontaccessible switchgear assembly 100 is exemplarily illustrated in FIGS.4A-4B, FIG. 16B, and FIG. 16D.

FIG. 4B exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly 100, showing support brackets 121for protecting the infrared windows 108 positioned on a rear side 100 bof the front accessible switchgear assembly 100. The infrared window 108positioned on a rear side 100 b of the front accessible switchgearassembly 100 allows rear scanning of, for example, the bus bars 103 inthe rear compartment 102 e defined in the electrical enclosure 101 forinspection and maintenance. The inspection windows 109 positioned on arear side 100 b of the front accessible switchgear assembly 100 providesa rear visual indication of, for example, the bus bars 103 in the rearcompartment 102 e defined in the electrical enclosure 101 for inspectionand maintenance.

FIG. 5 exemplarily illustrates a cut-away right perspective view of thefront accessible switchgear assembly 100, showing a control powertransformer 119 electrically connected in a middle compartment 102 b andan epoxy encapsulated potential transformer 120 electrically connectedin a lower compartment 102 c of the front accessible switchgear assembly100. FIG. 5 also illustrates the electrical connection of the upperhorizontal bus bars 103 a to the lower horizontal bus bars 103 d via thetransitional bus bars 103 b disposed in the second section 101 b of theelectrical enclosure 101.

FIG. 6 and FIG. 7 exemplarily illustrate a left perspective view and aleft orthogonal view of the front accessible switchgear assembly 100respectively. Each of the compartments 102 accessible from the frontside 100 a of the front accessible switchgear assembly 100 are providedwith doors 115 that can be opened for allowing front access to theelectrical cables 111, the electrical components 113, 118, 119, 120,etc., and the bus bars 103 for inspection and maintenance. The plenumchamber 105 is rearwardly positioned in the first section 101 a of theelectrical enclosure 101 as disclosed in the detailed description ofFIG. 1.

FIG. 8 exemplarily illustrates a front orthogonal view of the frontaccessible switchgear assembly 100, showing an infrared window 108 andinspection windows 109 positioned at predetermined locations on thefront side 100 a of the front accessible switchgear assembly 100. Doors115 are provided for accessing the compartments 102 defined in the firstsection 101 a and the second section 101 b of the electrical enclosure101. The infrared windows 108 and the inspection windows 109 areoperably positioned on the doors 115 of each of the compartments 102 onthe front side 100 a of the front accessible switchgear assembly 100.The infrared windows 108 allow front scanning of the electrical cables111, the electrical components 118, 119, etc., and the bus bars 103 inthe compartments 102 for inspection and maintenance. The infraredwindows 108 allow an infrared scan for any signs of overheating of theelectrical components, for example, the circuit breaker 118, theelectrical cables 111, and the bus bars 103, without the requirement ofprotective gear or clothing. The infrared windows 108 disclosed hereindo not rupture during arc testing.

The inspection windows 109, for example, windows made of Lexan® of SaudiBasic Industries Corp, provide a front visual indication of theelectrical cables 111, the electrical components 113, 118, 119, 120,etc., and the bus bars 103 in the compartments 102 for signs of heatingof the electrical cables 111, the electrical components 113, 118, 119,120, etc., and the bus bars 103 or any other abnormal conditions. Lexan®is a polycarbonate resin thermoplastic material manufactured by SaudiBasic Industries Corp used to construct the inspection windows 109 forthe front accessible switchgear assembly 100. The inspection windows 109provide an indication of a malfunction of any of the electrical cables111, the electrical components 113, 118, 119, 120, etc. For example, theinspection windows 109 provide indications of the circuit breaker 118from the front side 100 a of the front accessible switchgear assembly100. In an embodiment, the central compartment 102 d is, for example,covered with an inspection window 109 made of Lexan®. The supportbrackets 121 protect the infrared windows 108 and the inspection windows109 from rupture.

FIG. 9 exemplarily illustrates a rear perspective view of the frontaccessible switchgear assembly 100, showing infrared windows 108 andinspection windows 109 positioned at predetermined locations on the rearside 100 b of the front accessible switchgear assembly 100. The infraredwindows 108 positioned on the rear side 100 b of the front accessibleswitchgear assembly 100 allow rear scanning of, for example, the busbars 103 in the rear compartments 102 e, as exemplarily illustrated inFIG. 4B, defined in the first section 101 a and the second section 101 bof the electrical enclosure 101 for inspection and maintenance. Theinspection windows 109 positioned on the rear side 100 b of the frontaccessible switchgear assembly 100 provides a rear visual indication of,for example, the bus bars 103 in the rear compartments 102 e, asexemplarily illustrated in FIG. 4B, defined in the first section 101 aand the second section 101 b of the electrical enclosure 101 forinspection and maintenance.

FIG. 10 exemplarily illustrates a bottom orthogonal view of the frontaccessible switchgear assembly 100, showing a front lower compartment102 c of the front accessible switchgear assembly 100 configured forenabling electrical cables 111 to enter into and/or exit out from theelectrical enclosure 101. The bottom of the front lower compartment 102c defined in the first section 101 a of the electrical enclosure 101comprises cable entry and exit windows 122 that allow the electricalcables 111 to enter into and/or exit out from the front lowercompartment 102 c of the front accessible switchgear assembly 100. Inthis embodiment, the front accessible switchgear assembly 100 allowsfront access to the electrical cables 111 accommodated in the frontlower compartment 102 c of the front accessible switchgear assembly 100.

FIG. 11A exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly 100, showing a circuit breaker 118electrically connected in a middle compartment 102 b of the frontaccessible switchgear assembly 100. FIG. 11A also illustrates the upperhorizontal bus bars 103 a electrically connected in the centralcompartment 102 d defined in the first section 101 a of the electricalenclosure 101. Tulip contacts 118 f connected to the arms 118 c of thecircuit breaker 118 are mounted in the mounting block assembly 104, whenthe circuit breaker 118 is racked in the middle compartment 102 b. Thetulip contacts 118 f of the circuit breaker 118 contact a cylindricalbus 104 c running inside the mounting block assembly 104 as exemplarilyillustrated in FIG. 21D. As exemplarily illustrated in FIG. 11A, thefront accessible switchgear assembly 100 comprises two mounting blockassemblies 104 for accommodating incoming circuit breaker connections118 e and outgoing circuit breaker connections 118 d. The currenttransformers 113 are mounted on both the mounting block assemblies 104that accommodate the incoming circuit breaker connections 118 e and theoutgoing circuit breaker connections 118 d.

FIG. 11B exemplarily illustrates a bottom orthogonal view of the frontaccessible switchgear assembly 100 of FIG. 11A, showing the electricalcables 111 entering into the electrical enclosure 101 via the frontlower compartment 102 c defined in the first section 101 a of theelectrical enclosure 101. The bottom of the front lower compartment 102c defined in the first section 101 a of the electrical enclosure 101comprises cable entry and exit windows 122 that allow the electricalcables 111 to enter into and/or exit out from the front lowercompartment 102 c of the front accessible switchgear assembly 100.

As exemplarily illustrated in FIG. 11A, the cable connection bus bars103 c extend from the mounting block assembly 104 to the electricalcables 111 electrically connected in the front lower compartment 102 cdefined in the first section 101 a of the electrical enclosure 101. Whenthe electrical cables 111 are electrically connected in the front lowercompartment 102 c, the front lower compartment 102 c and the rearcompartment 102 e defined in the first section 101 a of the electricalenclosure 101 are essentially a single compartment with no sheet metalbarriers 101 e. In an embodiment, where an electrical component, forexample, the epoxy encapsulated potential transformer 120, is mounted inthe front lower compartment 102 c, the front lower compartment 102 c andthe rear compartment 102 e defined in the second section 101 b of theelectrical enclosure 101 are separated by barriers 101 e as exemplarilyillustrated in FIG. 12.

FIG. 12 exemplarily illustrates a cut-away right orthogonal view of thefront accessible switchgear assembly 100, showing a control powertransformer 119 electrically connected in a middle compartment 102 b andan epoxy encapsulated potential transformer 120 electrically connectedin a lower compartment 102 c of the front accessible switchgear assembly100. Upper horizontal bus bars 103 a disposed in the rear compartment102 e defined in the second section 101 b of the electrical enclosure101 are connected to the lower horizontal bus bars 103 d via thetransitional bus bars 103 b. FIG. 12 also illustrates the upper lowvoltage compartment 107, the exhaust chamber 112, and the plenum chamber105 as disclosed in the detailed description of FIG. 1. When anelectrical component, for example, the control power transformer 119, ismounted in the middle compartment 102 b defined in the second section101 b of the electrical enclosure 101, the middle compartment 102 b andthe rear compartment 102 e defined in the second section 101 b of theelectrical enclosure 101 are separated by a barrier 101 d. When anelectrical component, for example, the epoxy encapsulated potentialtransformer 120, is mounted in the lower compartment 102 c defined inthe second section 101 b of the electrical enclosure 101, the lowercompartment 102 c and the rear compartment 102 e defined in the secondsection 101 b of the electrical enclosure 101 are separated by a barrier101 e.

In an embodiment, the front accessible switchgear assembly 100 disclosedherein further comprises one or more fuse sleeve assemblies 120 aoperably connected to the epoxy encapsulated potential transformer 120as disclosed in the detailed description of FIGS. 23A-23E. If the epoxyencapsulated potential transformer 120 is mounted in the middlecompartment 102 b defined in the second section 101 b of the electricalenclosure 101 and if there is an arcing event in the middle compartment102 b, the gases are directed to the exhaust chamber 112 via the flap106 b exemplarily illustrated in FIG. 1A, into the plenum chamber 105.The fuse sleeve assemblies 120 a operably connected to the epoxyencapsulated potential transformer 120 contact the cylindrical bus 104 cthat runs inside the mounting block assembly 104, as exemplarilyillustrated in FIG. 23E, within the electrical enclosure 101, therebycreating an ultra compact front accessible switchgear assembly 100.

In an embodiment, the front accessible switchgear assembly 100 disclosedherein further comprises one or more fuse sleeve assemblies 119 aoperably connected to the control power transformer 119 as disclosed inthe detailed description of FIGS. 22A-22E. The fuse sleeve assemblies119 a operably connected to the control power transformer 119 contact,for example, the cylindrical bus 104 c that runs inside the mountingblock assembly 104, as exemplarily illustrated in FIG. 22E, within theelectrical enclosure 101, thereby creating an ultra compact frontaccessible switchgear assembly 100. The fuse sleeve assemblies 119 a and120 a of the control power transformer 119 and the epoxy encapsulatedpotential transformer 120 respectively contact one or more of the busbars 103, for example, in a rear compartment 102 e within the electricalenclosure 101 via the mounting block assembly 104. The configuration andfunctioning of the fuse sleeve assemblies 119 a and 120 a of the controlpower transformer 119 and the epoxy encapsulated potential transformer120 respectively in the front accessible switchgear assembly 100 alsoapply to the multi-access switchgear assembly 1700 exemplarilyillustrated in FIG. 17, FIG. 18A, and FIG. 19A.

FIG. 13 exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly 100, showing the electrical cables111 electrically connected to the upper horizontal bus bars 103 a viathe cable connection bus bars 103 c. The upper low voltage compartment107 is isolated from the plenum chamber 105 via the exhaust chamber 112.The exhaust chamber 112 isolates the gases from the plenum chamber 105from entering the upper low voltage compartment 107, for example, byusing a sheet metal barrier. In the front accessible switchgear assembly100 exemplarily illustrated in FIG. 13, the middle compartment 102 b canaccommodate the control power transformer 119 or the epoxy encapsulatedpotential transformer 120. The middle compartment 102 b can also beconfigured as a low voltage compartment 107.

FIGS. 14A-14B exemplarily illustrate cut-away left orthogonal views of asecond section 101 b of the front accessible switchgear assembly 100,showing electrical connection of the upper horizontal bus bars 103 afrom a first section 101 a of the electrical enclosure 101 to the lowerhorizontal bus bars 103 d in the second section 101 b of the electricalenclosure 101 via the transitional bus bars 103 b.

The upper horizontal bus bars 103 a and the lower horizontal bus bars103 d can be configured to connect adjacent sections 101 a and 101 b ofa single front accessible switchgear assembly 100 and/or adjacentswitchgear assemblies. In an embodiment, the upper horizontal bus bars103 a are electrically connected to the lower horizontal bus bars 103 dvia, for example, the circuit breaker 118 as exemplarily illustrated inFIG. 15. In an embodiment, the upper horizontal bus bars 103 a runbetween the first section 101 a and the second section 101 b of theelectrical enclosure 101 of the front accessible switchgear assembly 100to electrically connect the upper horizontal bus bars 103 a to theoutput of the circuit breaker 118. In another embodiment, the upperhorizontal bus bars 103 a are configured to electrically connect to theelectrical cables 111 in the lower compartment 102 c defined in thefirst section 101 a of the electrical enclosure 101. The frontaccessible switchgear assembly 100 disclosed herein allows flexibilityin configuring the bus bars 103 for any electrical connections requiredin the electrical enclosure 101.

Also illustrated in FIG. 14B is the control power transformer 119electrically connected in the middle compartment 102 b defined in thesecond section 101 b of the electrical enclosure 101, and the epoxyencapsulated potential transformer 120 electrically connected in thelower compartment 102 c defined in the second section 101 b of theelectrical enclosure 101. The internal fuse clips 119 b and 120 b of thecontrol power transformer 119 and the epoxy encapsulated potentialtransformer 120 respectively exemplarily illustrated in FIG. 14B, aredisclosed in the detailed description of FIGS. 22A-22E and FIGS. 23A-23Erespectively.

FIG. 15 exemplarily illustrates a cut-away left orthogonal view of thefirst section 101 a of the front accessible switchgear assembly 100,showing the upper horizontal bus bars 103 a accommodated in a centralcompartment 102 d defined in the first section 101 a of the frontaccessible switchgear assembly 100 and electrically connected to thelower horizontal bus bars 103 d that extend into the second section 101b of the front accessible switchgear assembly 100, via mounting blockassemblies 104 with a mounted circuit breaker 118. In this embodiment,the upper horizontal bus bars 103 a are connected to the lowerhorizontal bus bars 103 d in the rear compartment 102 e of theelectrical enclosure 101 via the mounting block assemblies 104 with themounted circuit breaker 118. The circuit breaker 118 is electricallyconnected in the middle compartment 102 b defined in the first section101 a of the electrical enclosure 101. The tulip contacts 118 f on thearms 118 c of the circuit breaker 118 contact the cylindrical bus 104 cthat runs inside each of the mounting block assemblies 104, asexemplarily illustrated in FIG. 21D, which extend into the centralcompartment 102 d and the rear compartment 102 e defined in the firstsection 101 a of the electrical enclosure 101 as exemplarily illustratedin FIG. 15.

FIG. 16A exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly 100, showing an upper compartment102 a of the front accessible switchgear assembly 100 configured forenabling the electrical cables 111 to enter into and/or exit out fromthe electrical enclosure 101, where the electrical cables 111 areelectrically connected to the upper horizontal bus bars 103 a via thecable connection bus bars 103 c. In this embodiment, the frontaccessible switchgear assembly 100 further comprises cable entry andexit windows 122 defined on the upper end 101 f of the electricalenclosure 101. The electrical cables 111 enter the front uppercompartment 102 a defined in the electrical enclosure 101 via the cableentry and exit windows 122. In this embodiment, the front uppercompartment 102 a is a full section extending from the upper end 101 fof the electrical enclosure 101 towards the front lower compartment 102c in the electrical enclosure 101. When the electrical cables 111 extendinto the upper compartment 102 a from the upper end 101 f of theelectrical enclosure 101 via the cable entry and exit windows 122, thefront upper compartment 102 a and the middle compartment 102 b definedin the electrical enclosure 101 are essentially a single compartmentwith no sheet metal barriers. In this embodiment, the electrical cables111 extend into the front upper compartment 102 a and electricallyconnect to the upper horizontal bus bars 103 a in the rear compartment102 e defined in the electrical enclosure 101 via the cable connectionbus bars 103 c. In an embodiment, the electrical cables 111 are directlyconnected to the upper horizontal bus bars 103 a. The compartments, forexample, 102 a, 102 c, etc., that accommodate the electrical cables 111cannot be configured as a low voltage compartment 107. In the frontaccessible switchgear assembly 100 exemplarily illustrated in FIG. 16A,the lower compartment 102 c can accommodate the epoxy encapsulatedpotential transformer 120. The lower compartment 102 c can also beconfigured as a low voltage compartment 107.

FIG. 16B exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly 100, showing an upper compartment102 a of the front accessible switchgear assembly 100 configured forenabling the electrical cables 111 to enter into and/or exit out fromthe electrical enclosure 101. FIG. 16B also illustrates a supportbracket 121 that protects an infrared window 108 positioned on the frontside 100 a of the front accessible switchgear assembly 100. In anembodiment, a support bracket 121 is also provided for protecting aninfrared window 108 positioned on the rear side 100 b of the frontaccessible switchgear assembly 100 as exemplarily illustrated in FIG.4B. The support bracket 121 is connected below the infrared window 108for protecting the infrared window 108 from rupture due to the pressureof gases during an event of arcing. In the event of arcing in the lowercompartment 102 c, gases exit through the flap 106 c through the exhaustchamber 112 via the flap 106 b, and into the plenum chamber 105 asexemplarily illustrated in FIG. 1A.

FIG. 16C exemplarily illustrates a cut-away left orthogonal view of thefront accessible switchgear assembly 100, showing an upper compartment102 a of the front accessible switchgear assembly 100 configured forenabling the electrical cables 111 to enter into and/or exit out fromthe electrical enclosure 101. The electrical cables 111 are electricallyconnected to the lower horizontal bus bars 103 d via the cableconnection bus bars 103 c.

FIG. 16D exemplarily illustrates a cut-away left perspective view of thefront accessible switchgear assembly 100, showing an upper compartment102 a of the front accessible switchgear assembly 100 configured forenabling the electrical cables 111 to enter into and/or exit out fromthe electrical enclosure 101. FIG. 16D also illustrates a supportbracket 121 that protects an infrared window 108 positioned on the frontside 100 a of the front accessible switchgear assembly 100. The supportbracket 121 below the infrared window 108 protects the infrared window108 from rupture due to the pressure of gases during an event of arcing.In the event of arcing in the lower compartment 102 c, gases exitthrough the flap 106 c through the exhaust chamber 112 via the flap 106b, and into the plenum chamber 105 as exemplarily illustrated in FIG.1A.

FIG. 17 exemplarily illustrates a cut-away left perspective view of amulti-access switchgear assembly 1700, showing electrical cables 111accommodated in a rear lower compartment 102 e, a circuit breaker 118accommodated in a middle compartment 102 b, and an epoxy encapsulatedpotential transformer 120 accommodated in a front lower compartment 102c, in a single section 101 a of the multi-access switchgear assembly1700. The multi-access switchgear assembly 1700 disclosed hereincomprises a compact and arc resistant electrical enclosure 101, multiplecompartments 102 defined within the electrical enclosure 101, one ormore mounting block assemblies 104, a plenum chamber 105, electricalcables 111, electrical components 113, 118, 119, 120, etc., asexemplarily illustrated in FIG. 17 and FIG. 18A, and bus bars 103, forexample, 103 a, 103 b, 103 c, etc. The compartments 102 are configuredto interchangeably accommodate one or more electrical components 113,118, 119, 120, etc., the electrical cables 111, and the bus bars 103.The configuration and functioning of the compartments 102, the lowvoltage compartment 107, the electrical components 113, 118, 119, 120,etc., the plenum chamber 105, the flaps 106 a, 106 b, 106 c, etc., andthe bus bars 103 of the multi-access switchgear assembly 1700 are thesame as that disclosed for the front accessible switchgear assembly 100in the detailed description of FIGS. 1A-16D.

The multi-access switchgear assembly 1700 disclosed herein is a metalclad switchgear assembly. Adjacent sections 101 a and 101 b defined inthe electrical enclosure 101 of the multi-access metal clad switchgearassembly 1700 are separated by vertical metal barriers 101 c forcompartmentalizing active electrical components 118, 119, 120, etc., inthe electrical enclosure 101. The multi-access metal clad switchgearassembly 1700 has a higher duty cycle and a greater number of loadoperations, for example, about 10 times to about 1000 times greaternumber of load operations than that of a metal enclosed switchgearassembly. The “multi-access metal clad switchgear assembly” is hereinreferred to as a “multi-access switchgear assembly”.

The multi-access switchgear assembly 1700 disclosed herein refers to a15000 volts (V) switchgear assembly and can be extended to higher andlower voltages. The multi-access switchgear assembly 1700 disclosedherein accommodates 15 kilovolt (kV) class equipment and providessolutions for 95 kV lightning impulse voltage and 1200 ampere (A) ratingwith a control power transformer 119 as exemplarily illustrated in FIG.18A, rated up to 15 kVA. The multi-access switchgear assembly 1700disclosed herein can be extended to higher ratings and can be used forlow voltage switchgear assemblies rated 600V and below.

The multi-access switchgear assembly 1700 is compact and is configuredwith a depth of, for example, about 72 inches for front and rearaccessibility. The width and height of each of the sections 101 a and101 b of the electrical enclosure 101 of the multi-access switchgearassembly 1700 are, for example, about 23.62 inches and about 96 inchesrespectively. The multi-access switchgear assembly 1700 requires aminimum clearance of, for example, about 60 inches from a wall forproviding rear access to the multi-access switchgear assembly 1700, withreduced width requirements. Working clearance of about 5 feet or more isprovided in the front and the rear of the multi-access switchgearassembly 1700. The multi-access switchgear assembly 1700 is configuredto line up with a switchgear having a current rating of about 2000amperes, thereby enabling usage of circuit breakers 118 having currentratings of about 1200 amperes and 2000 amperes.

The plenum chamber 105 is in communication with one or more of thecompartments 102 and in adjacent communication with the exhaust chamber112. The plenum chamber 105 provides an exit path for releasing pressureand gases generated by one or more of the electrical components 113,118, 119, 120, etc., and the electrical cables 111 accommodated in thecompartments 102 during an event of arcing within the electricalenclosure 101. The multi-access switchgear assembly 1700 disclosedherein can accommodate a plenum chamber 105 with more depth and volumecompared to the front accessible switchgear assembly 100 exemplarilyillustrated in FIGS. 1A-16D, due to which the pressure within thevarious compartments 102 of the multi-access switchgear assembly 1700during an arcing event within the electrical enclosure 101 is lowercompared to that of the front accessible switchgear assembly 100. Thecompartments 102 of the multi-access switchgear assembly 1700 areconfigured to minimize the pressure of gases during an arcing event.Moreover, the volume of the lower compartments 102 c is larger in themulti-access switchgear assembly 1700 and therefore there is lesspressure build up during an arcing event.

One or more of the compartments 102 defined within the electricalenclosure 101 of the multi-access switchgear assembly 1700 is configuredfor enabling the electrical cables 111 to enter into and/or exit outfrom the electrical enclosure 101 for allowing front access and/or rearaccess to the electrical cables 111. For example, a front lowercompartment 102 c and/or a rear lower compartment 102 e are configuredfor enabling the electrical cables 111 to enter into and/or exit outfrom the electrical enclosure 101 for allowing front access and/or rearaccess to the electrical cables 111 respectively. As exemplarilyillustrated in FIG. 17, the multi-access switchgear assembly 1700 allowsrear access to the electrical cables 111 accommodated in the rear lowercompartment 102 e of the multi-access switchgear assembly 1700.

In the multi-access switchgear assembly 1700 exemplarily illustrated inFIG. 17, the front lower compartment 102 c accommodates the epoxyencapsulated potential transformer 120, while the middle compartment 102b accommodates the circuit breaker 118. The circuit breaker 118 contactsone or more of the bus bars 103 via the mounting block assembly 104. Inthis embodiment, the epoxy encapsulated potential transformer 120 isaccommodated in the front lower compartment 102 c of the multi-accessswitchgear assembly 1700, while the electrical cables 111 areaccommodated in the rear lower compartment 102 e of the multi-accessswitchgear assembly 1700. The epoxy encapsulated potential transformer120, the electrical cables 111, and the circuit breaker 118 aretherefore positioned in a single section 101 a of the multi-accessswitchgear assembly 1700, thereby minimizing the need for additionalsections in the multi-access switchgear assembly 1700. The multi-accessswitchgear assembly 1700, exemplarily illustrated in FIG. 17, providesfront access to the circuit breaker 118 and the epoxy encapsulatedpotential transformer 120.

In an embodiment, where the epoxy encapsulated potential transformer 120is mounted in the front lower compartment 102 c, and the electricalcables 111 are mounted in the rear lower compartment 102 e defined inthe first section 101 a of the electrical enclosure 101 of themulti-access switchgear assembly 1700, the front lower compartment 102 cand the rear lower compartment 102 e defined in the electrical enclosure101 are separated by barriers 101 e as exemplarily illustrated in FIG.17.

The multi-access switchgear assembly 1700 exemplarily illustrated inFIG. 17 further comprises one or more inspection windows 109 positionedat predetermined locations on one or more of a front side 1700 a and arear side 1700 b of the multi-access switchgear assembly 1700. Theinspection windows 109, for example, windows made of Lexan® of SaudiBasic Industries Corp, provide a front visual indication and/or a rearvisual indication of the electrical components 113, 118, 119, 120, etc.,the electrical cables 111, and the bus bars 103 in the compartments 102for signs of heating of the electrical components 113, 118, 119, 120,etc., the electrical cables 111, and the bus bars 103 or any otherabnormal conditions. The multi-access switchgear assembly 1700 furthercomprises one or more infrared windows 108 positioned at predeterminedlocations on one or more of a front side 1700 a and a rear side 1700 bof the multi-access switchgear assembly 1700 for front scanning and/orrear scanning of the electrical components 113, 118, 119, 120, etc., theelectrical cables 111, and the bus bars 103 in the compartments 102 forinspection and maintenance. The bus bars 103 are electrically connected,for example, in the rear compartments 102 e of the multi-accessswitchgear assembly 1700. The multi-access switchgear assembly 1700disclosed herein allows flexibility in configuring the bus bars 103 forany electrical connections required in the electrical enclosure 101.

In an embodiment, the multi-access switchgear assembly 1700 furthercomprises surge arresters 116 not shown in FIG. 17. The surge arresters116 are positioned, for example, in the rear compartments 102 e definedin the electrical enclosure 101 for protecting the electrical components113, 118, 119, 120, etc., the bus bars 103, the inspection windows 109,the infrared windows 108, the electrical cables 111, the mounting blockassembly 104, the compartments 102 defined within the electricalenclosure 101, etc., in an event of a lightning surge. The surgearresters 116 are electrically connected to one or more of the bus bars103 in the electrical enclosure 101 via short high voltage electricalcables 110.

FIG. 17 also illustrates insulating boots 123 for the mounting blockassembly 104. The insulating boots 123 are flexible boot like coversthat enclose exposed bus bars 103 in the multi-access switchgearassembly 1700. The insulating boots 123 provide additional insulationwhich increases creepage distance and helps in withstanding lightningimpulses over time as insulators degrade. The insulating boots 123therefore help maintain long-term reliability of the multi-accessswitchgear assembly 1700. The insulating boots 123 are custom designedfor each multi-access switchgear assembly 1700 and tightly fit toenclose the exposed bus bars 103, thereby ensuring proper insulation.Moreover, the insulating boots 123 leave no part of live or active busbars 103 carrying electric current exposed, thereby ensuring that noaccidental contact occurs with the live bus bars 103 when the doors 115,as exemplarily illustrated in FIGS. 1A-1B, FIG. 6, etc., provided foraccessing the compartments 102 defined in the first section 101 a andthe second section 101 b of the electrical enclosure 101 are opened formaintenance.

In the multi-access switchgear assembly 1700 exemplarily illustrated inFIG. 17, the insulating boots 123 cover an exposed bus attached to thecylindrical bus 104 c that runs inside each of the mounting legs 104 aof the mounting block assembly 104 exemplarily illustrated in FIG. 20Aand FIG. 20C. Custom insulating boots (not shown) also cover exposedends of the upper horizontal bus bars 103 a. Moreover, other custominsulating boots (not shown) cover the exposed bus bars 103 that connectthe electrical cables 111, the epoxy encapsulated potential transformer120, the control power transformer 119, and the surge arresters 116within the electrical enclosure 101.

As exemplarily illustrated in FIG. 17, the multi-access switchgearassembly 1700 comprises two mounting block assemblies 104 foraccommodating incoming circuit breaker connections 118 e and outgoingcircuit breaker connections 118 d. The current transformers 113 aremounted on both the mounting block assemblies 104 that accommodate theincoming circuit breaker connections 118 e and the outgoing circuitbreaker connections 118 d.

FIG. 18A exemplarily illustrates a cut-away left perspective view of themulti-access switchgear assembly 1700, showing electrical cables 111accommodated in the rear lower compartment 102 e of the multi-accessswitchgear assembly 1700 and electrically connected to the upperhorizontal bus bars 103 a via the cable connection bus bars 103 c. Inthe multi-access switchgear assembly 1700 exemplarily illustrated inFIG. 18A, the middle compartment 102 b accommodates the control powertransformer 119, the front lower compartment 102 c accommodates theepoxy encapsulated potential transformer 120, and the rear lowercompartment 102 e accommodates the electrical cables 111. Themulti-access switchgear assembly 1700, exemplarily illustrated in FIG.18A, provides front access to the control power transformer 119 and theepoxy encapsulated potential transformer 120. In this embodiment, theupper compartment 102 a can be configured as the low voltage compartment107 for accommodating control equipment. The low voltage compartment 107is isolated from the plenum chamber 105 and other compartments 102 b,102 c, etc. The configuration and functioning of the low voltagecompartment 107 is disclosed in the detailed description of FIGS. 1A-1B.

Moreover, the electrical cables 111 are connected to the upperhorizontal bus bars 103 a via the cable connection bus bars 103 c. In anembodiment, the electrical cables 111 are directly connected to theupper horizontal bus bars 103 a. As exemplarily illustrated in FIG. 18A,the multi-access switchgear assembly 1700 allows rear access to theelectrical cables 111 accommodated in the rear lower compartment 102 eof the multi-access switchgear assembly 1700. The epoxy encapsulatedpotential transformer 120, the electrical cables 111, and the controlpower transformer 119 are positioned in a single section 101 a of themulti-access switchgear assembly 1700, thereby minimizing the need foradditional sections in the multi-access switchgear assembly 1700.

In an embodiment, one or more of the horizontal bus bars, for example,103 a electrically connected, for example, in the rear compartments 102e within the electrical enclosure 101 allow connection to adjacentsections 101 a and 101 b defined in the electrical enclosure 101,connection between the electrical components 118, 119, 120, etc., in theadjacent sections 101 a and 101 b defined in the electrical enclosure101, connection between the electrical cables 111 in adjacentcompartments 102 in the electrical enclosure 101 as exemplarilyillustrated in FIG. 19A, and in the adjacent sections 101 a and 101 bdefined in the electrical enclosure 101, and connection to one or moreother switchgear assemblies. The multi-access switchgear assembly 1700can be configured to line up with a switchgear having a current ratingof, for example, about 2000 amperes using the horizontal bus bars 103 arated 2000 amperes, thereby enabling usage of the circuit breakers 118having current ratings of, for example, about 1200 amperes and 2000amperes in a single line up.

FIG. 18B exemplarily illustrates a bottom orthogonal view of themulti-access switchgear assembly 1700 of FIG. 18A, showing theelectrical cables 111 entering into the electrical enclosure 101 via therear lower compartment 102 e of the multi-access switchgear assembly1700. The bottom of the rear lower compartment 102 e defined in theelectrical enclosure 101 comprises cable entry and exit windows 122 thatallow the electrical cables 111 to enter into and/or exit out from therear lower compartment 102 e of the multi-access switchgear assembly1700. The lower horizontal bus bars 103 d extending outwardly from themulti-access switchgear assembly 1700, for example, allow connection toone or more other switchgear assemblies.

FIG. 19A exemplarily illustrates a cut-away left perspective view of themulti-access switchgear assembly 1700, showing electrical cables 111accommodated in the front lower compartment 102 c and the rear lowercompartment 102 e of the multi-access switchgear assembly 1700. FIG. 19Aalso illustrates cable connection bus bars 103 c that connect theelectrical cables 111 in the front lower compartment 102 c and the rearlower compartment 102 e of the multi-access switchgear assembly 1700 tothe upper horizontal bus bars 103 a. In this embodiment, themulti-access switchgear assembly 1700 allows front access and rearaccess to the electrical cables 111 accommodated in the front lowercompartment 102 c and the rear lower compartment 102 e of themulti-access switchgear assembly 1700 respectively. Furthermore, in thisembodiment, the upper compartment 102 a is configured as the low voltagecompartment 107 and the middle compartment 102 b accommodates thecircuit breaker 118. The multi-access switchgear assembly 1700,exemplarily illustrated in FIG. 19A, provides front access to thecircuit breaker 118.

FIG. 19B exemplarily illustrates a bottom orthogonal view of themulti-access switchgear assembly 1700 of FIG. 19A, showing theelectrical cables 111 entering into the electrical enclosure 101 via thefront lower compartment 102 c and the rear lower compartment 102 e ofthe multi-access switchgear assembly 1700. The bottom of the front lowercompartment 102 c and the rear lower compartment 102 e defined in theelectrical enclosure 101 comprises cable entry and exit windows 122 thatallow the electrical cables 111 to enter into and/or exit out from thefront lower compartment 102 c and the rear lower compartment 102 e ofthe multi-access switchgear assembly 1700 respectively.

FIGS. 20A-20C exemplarily illustrate perspective views of a mountingblock assembly 104 for the front accessible switchgear assembly 100 andthe multi-access switchgear assembly 1700. The mounting block assembly104 for the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 is configured as a monoblock formounting the electrical components 113, 118, 119, 120, etc., in thefront accessible switchgear assembly 100 and the multi-access switchgearassembly 1700. As used herein, the term “monoblock” refers to a blockconfiguration that accommodates all three phases in the electricalenclosure 101. The monoblock configuration of the mounting blockassembly 104 allows compact arrangement of the electrical components113, 118, 119, 120, etc., in the electrical enclosure 101, therebyproviding a compact front accessible switchgear assembly 100 and acompact multi-access switchgear assembly 1700. The monoblockconfiguration requires a large compression mold and is configured tomeet Underwriters Laboratories (UL) flame and tracking tests for a 15 kVfront accessible switchgear assembly 100 and a 15 kV multi-accessswitchgear assembly 1700.

The mounting block assembly 104 comprises a base mounting block 104 b,mounting legs 104 a, and a mounting block cover 104 d. The mountingblock assembly 104 is positioned in one or more of the compartments 102defined in the first section 101 a and the second section 101 b of theelectrical enclosure 101, as exemplarily illustrated in FIGS. 1A-1B,FIGS. 2-5, FIG. 11A, FIG. 12, FIG. 15, FIG. 17, FIG. 18A, and FIG. 19A,for mounting one or more of the electrical components, for example, oneor more current transformers 113 having one of multiple current ratios.The current transformers 113 are used for metering or relaying in thefront accessible switchgear assembly 100 and the multi-access switchgearassembly 1700. Each current transformer 113 mounted on a mounting leg104 a of one mounting block assembly 104 has the same current ratio, forexample, 1200:5. The current transformers 113 mounted on a mounting leg104 a of another mounting block assembly 104 in another section 101 a or101 b of the electrical enclosure 101 may have a different currentratio, for example, 600:5 or 300:5. Therefore, in the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700, amounting block assembly 104 in one of the compartments 102 mountscurrent transformers 113 having a current ratio of 1200:5, while anothermounting block assembly 104 in another one of the compartments 102mounts current transformers 113 having a current ratio of 600:5 or300:5.

The mounting legs 104 a extend frontwardly from the base mounting block104 b, as exemplarily illustrated in FIG. 20A, for mounting theelectrical components 113, 118, 119, 120, etc., and for allowing frontaccess to the mounted electrical components 113, 118, 119, 120, etc.,for inspection and maintenance. A cylindrical bus 104 c, for example,made of copper runs inside each of the mounting legs 104 a of themounting block assembly 104. The cylindrical bus 104 c is configured,for example, as a copper pin. The cylindrical bus 104 c extendsfrontwardly to contact the electrical components, for example, thecircuit breaker 118 mounted in the mounting block assembly 104. Forexample, the cylindrical bus 104 c of the mounting block assembly 104contacts each of the tulip contacts 118 f of the circuit breaker 118when the circuit breaker 118 is racked in the middle compartment 102 bdefined in the first section 101 a of the electrical enclosure 101 asexemplarily illustrated in FIGS. 21C-21D.

In another example, the cylindrical bus 104 c of the mounting blockassembly 104 contacts each of the fuse sleeve assemblies 119 a of thecontrol power transformer 119, when the control power transformer 119 isracked in the middle compartment 102 b defined in the second section 101b of the electrical enclosure 101 as exemplarily illustrated in FIGS.22D-22E. In another example, the cylindrical bus 104 c of the mountingblock assembly 104 contacts each of the fuse sleeve assemblies 120 a ofthe epoxy encapsulated potential transformer 120, when the epoxyencapsulated potential transformer 120 is racked in the lowercompartment 102 c defined in the second section 101 b of the electricalenclosure 101 as exemplarily illustrated in FIGS. 23D-23E.

The mounting block cover 104 d as exemplarily illustrated in FIG. 20B isremovably attached to the base mounting block 104 b for enclosing, forexample, the mounted current transformers 113 on the mounting legs 104 aas exemplarily illustrated in FIG. 20C. Brackets 104 e are provided onboth sides of the mounting block assembly 104 for enclosing the mountingblock cover 104 d and the mounted current transformers 113 on themounting legs 104 a and for providing support to the mounting blockassembly 104. The mounting block cover 104 d is removable for providingfront access to the mounted current transformers 113 for inspection,maintenance, and service. For example, the mounting block cover 104 dcan be removed from the front by operating personnel for inspecting thecurrent transformers 113 mounted on the mounting block assembly 104.

The mounting block assembly 104 with a pair of current transformers 113mounted on each of the mounting legs 104 a on the base mounting block104 b, where the pair of the current transformers 113 is enclosed by themounting block cover 104 d and the brackets 104 e is exemplarilyillustrated in FIG. 20C. The current transformer 113 is, for example, aring type current transformer with a voltage rating of, for example,about 600V. The compact design of the mounting block assembly 104 allowsusage of current transformers 113 of lower voltage rating, for example,about 600V, in the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 of a medium voltage, for example,about 15,000V. Each mounting block assembly 104 has rear busconnections. The cylindrical bus 104 c made of, for example, copper,runs inside the mounting legs 104 a of the mounting block assembly 104.When the circuit breaker 118 is mounted in the mounting block assembly104 in the middle compartment 102 b defined in the first section 101 aof the electrical enclosure 101, the tulip contacts 118 f on the arms118 c of the circuit breaker 118 make a solid electrical connection withthe cylindrical bus 104 c inside the mounting block assembly 104 asexemplarily illustrated in FIGS. 21C-21D. The cylindrical bus 104 c isin electrical communication with each of the tulip contacts 118 f of thecircuit breaker 118 inside the mounting block assembly 104.

The mounting block assembly 104 is configured to reduce temperature risein the compartments 102. For example, the material of the mounting blockassembly 104 is pigmented with a black colored material to limit thetemperature rise in the middle compartment 102 b that accommodates thecircuit breaker 118 to meet standards of Underwriters Laboratories® andother agency standards. The black colored material of the mounting blockassembly 104 keeps the temperature rise in the compartments 102 toallowable agency limits. The mounting block assembly 104 pigmented withthe black colored material acts as a black body and absorbs heat,thereby limiting the temperature rise of the electrical cables 111, theelectrical components 118, etc., for example, conductors of the circuitbreaker 118, and the bus bars 103. The use of black colored materialeliminates the need for expensive and bulky heat sinks required to limitthe temperature rise of the electrical cables 111, the electricalcomponents 118, etc., and the bus bars 103. The use of the black coloredmaterial for the mounting block assemblies 104, painting inside thecompartments 102 in black color, and use of larger cross section busbars 103 in the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 disclosed herein achieves acompact footprint.

The mounting block assembly 104 is, for example, made of a glasspolyester composition, plastics such as a polyethylene material, or anyother suitable material. Glass polyester requires a compression mold,while the polyethylene material uses a silicon mold for quick productionof the mounting block assembly 104. Other insulating materials and othermolding techniques can be employed for the manufacture of the mountingblock assembly 104.

The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 are configured to mount one or more low voltagecurrent transformers 113, for example, 600 volts current transformers ina high voltage circuit, for example, 15000 volts circuit. Mounting ofthe low voltage current transformers 113, for example, a 600V currenttransformers in high voltage and medium voltage circuits provides forspace and cost savings. The front accessible switchgear assembly 100 andthe multi-access switchgear assembly 1700 disclosed herein enablemounting of multiple current transformers 113 on each phase input andoutput. More than one current transformer 113 can be installed on eachmounting leg 104 a of the mounting block assembly 104. The currenttransformers 113 are configured, for example, for control, forprotection, etc. Furthermore, the current transformers 113 can beinstalled both on the input side and the output side of the circuitbreaker 118 via the mounting block assembly 104. In an embodiment,multiple mounting legs 104 a may be provided for mounting a number ofcurrent transformers 113 on the mounting block assembly 104 based on therequirements of the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700. In another embodiment, themounting legs 104 a can be elongated to accommodate multiple currenttransformers 113. Therefore, each mounting block assembly 104 canaccommodate multiple current transformers 113. The current transformers113 are, for example, metering type current transformers, and protectiontype current transformers, for example, relay class currenttransformers, etc. The current transformers 113 are adapted for savingspace in the electrical enclosure 101.

The current transformers 113 are, for example, ring type toroidaltransformers that are mounted on the mounting block assembly 104. Thecylindrical bus 104 c that runs inside the mounting legs 104 a of themounting block assembly 104 passes through each of the windows of thering type current transformers 113. The current transformer 113comprises primary turns and secondary turns. The turn ratio of theprimary turns to the secondary turns varies in accordance with theelectrical rating of the front accessible switchgear assembly 100 andthe multi-access switchgear assembly 1700. The electrical rating of thesecondary turns of the current transformer 113 is, for example, about 5A. In an embodiment, the electrical rating of the secondary turns of thecurrent transformer 113 is, for example, about 1 A. In an embodiment,the turn ratio of the primary turns to the secondary turns is, forexample, 1200:5. That is, the ratio of the primary turns to thesecondary turns can be interpreted as 1200 A to 5 A on a 1200:5 currenttransformer 113 comprising 1200 primary turns and 5 secondary turns.Current transformers 113 of turn ratios, for example, 2000:5, 600:5,300:5, etc., may also be utilized in the front accessible switchgearassembly 100 and the multi-access switchgear assembly 1700 disclosedherein. In an embodiment, the primary turns in the current transformer113 are, for example, electromagnetically coupled to the cylindrical bus104 c, for example, by induction. The front accessible switchgearassembly 100 and the multi-access switchgear assembly 1700 can thereforebe configured for current transformers 113 with lower electrical rating,for example, about 600V, in a medium voltage circuit with a rating of,for example, about 15,000V.

The mounting block assembly 104 provides sufficient creepage distancesuch that low voltage current transformers 113 are not exposed to highervoltages. Higher voltage current transformers are bulky and expensive.Using higher voltage current transformers in a small enclosure givesrise to space constrictions and heating of the other electricalcomponents, for example, 118, 119, 120, etc., of the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700due to the high voltages present on the higher voltage currenttransformers. Hence, the design of the base mounting block 104 b, themounting legs 104 a, and the mounting block cover 104 d provides thecreepage required for 95000V so that the low voltage currenttransformers 113 are protected and hence the low voltage currenttransformers 113, for example, 600V current transformers can be used tooptimize space and save cost. Furthermore, the low voltage currenttransformers 113 are lightweight, easier to install and replace, and areless costly compared to the higher voltage current transformers. The lowvoltage current transformers 113 are mounted, for example, with plasticscrews to the mounting block assembly 104 as exemplarily illustrated inFIG. 20C. In an embodiment, high voltage current transformers may alsobe mounted in a compact front accessible switchgear assembly 100 and acompact multi-access switchgear assembly 1700.

In the front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein, low voltage currenttransformers 113, for example, 600V can be used for medium voltageapplications at, for example, 15000V. This results in substantialsavings and makes a compact design of the front accessible switchgearassembly 100 and the multi-access switchgear assembly 1700 possible.More than one current transformer 113 can be installed on each mountingleg 104 a of the mounting block assembly 104. For example, one meteringcurrent transformer and one protection current transformer are mountedon each mounting leg 104 a of the mounting block assembly 104 for athree phase front accessible switchgear assembly 100 or a three phasemulti-access switchgear assembly 1700.

FIGS. 21A-21B exemplarily illustrate perspective views of a circuitbreaker 118 utilized in the front accessible switchgear assembly 100 andthe multi-access switchgear assembly 1700, showing tulip contacts 118 fof the circuit breaker 118. The circuit breaker 118 is electricallyconnected in, for example, the middle compartment 102 b defined in thefirst section 101 a of the electrical enclosure 101 as exemplarilyillustrated in FIG. 1B, FIG. 4A, FIG. 11A, FIG. 15, FIG. 17, and FIG.19A. The circuit breaker 118 is an automatically operated electricalswitch designed to protect the front accessible switchgear assembly 100and the multi-access switchgear assembly 1700 from damage caused by anoverload or a short circuit. The circuit breaker 118 detects a faultcondition in the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 and immediately discontinueselectrical flow by interrupting continuity. In an embodiment, one ormore current transformers 113 are electrically connected on an inputside of the circuit breaker 118 and an output side of the circuitbreaker 118.

A cord 118 a configured as, for example, an umbilical cord, iselectrically connected to the circuit breaker 118 for low voltageconnection within the electrical enclosure 101. The cord 118 a makes thelow voltage connection via a connector 118 b, for example, a maleconnector as exemplarily illustrated in FIGS. 21A-21B. The connector 118b is disposed in, for example, the middle compartment 102 b just abovethe circuit breaker 118. There is a positive connection when the circuitbreaker 118 is in a connected or racked-in position, or in a withdrawnor racked-out position. The use of the connector 118 b eliminates theneed for an additional test position to check the low voltageconnection. The circuit breaker 118 is mounted on a truck 118 g withrollers 118 h that roll on a track (not shown) positioned in the middlecompartment 102 b, for racking the circuit breaker 118 in and out of themiddle compartment 102 b. A racking tool (not shown) may be insertedinto a circular opening 118 j provided on the truck 118 g of the circuitbreaker 118 for racking the circuit breaker 118 in and out of the middlecompartment 102 b. The handles 118 i on the truck 118 g of the circuitbreaker 118 are used to remove the circuit breaker 118 from the track(not shown) in the middle compartment 102 b. The circuit breaker 118comprises the tulip contacts 118 f provided on the arms 118 c extendingoutwardly from the circuit breaker 118. Each of the tulip contacts 118 fof the circuit breaker 118 makes contact with the cylindrical bus 104 cthat runs inside each mounting leg 104 a of the mounting block assembly104, as exemplarily illustrated in FIG. 21D, in the middle compartment102 b defined in the first section 101 a of the electrical enclosure101.

FIG. 21C exemplarily illustrates a plan view showing connection of thecircuit breaker 118 within the mounting block assembly 104. Asexemplarily illustrated in FIG. 21C, ring type current transformers 113are mounted on the mounting legs 104 a of the mounting block assembly104. When the circuit breaker 118 is installed and racked into themiddle compartment 102 b, the tulip contacts 118 f on the arms 118 c ofthe circuit breaker 118 make electrical contact with the cylindrical bus104 c that runs inside the mounting legs 104 a of the mounting blockassembly 104.

FIG. 21D exemplarily illustrates a sectional view taken at section A-Aof FIG. 21C, showing connection of a tulip contact 118 f of the circuitbreaker 118 to a cylindrical bus 104 c that runs inside the mountingblock assembly 104. When the circuit breaker 118 is installed and rackedinto the middle compartment 102 b, the tulip contact 118 f housed oneach arm 118 c of the circuit breaker 118 enters the mounting blockcover 104 d and makes solid electrical contact with the cylindrical bus104 c that runs inside each mounting leg 104 a of the mounting blockassembly 104. Low voltage current transformers 113 are also installed onthe mounting legs 104 a of the mounting block assembly 104 and are inelectrical communication with the cylindrical bus 104 c that runs insideeach of the mounting legs 104 a of the mounting block assembly 104. Thelow voltage current transformers 113 measure current through thecylindrical bus 104 c.

For each circuit breaker 118, there are two mounting block assemblies104, one for incoming breaker connections 118 e and one for outgoingbreaker connections 118 d as exemplarily illustrated in FIG. 11A, FIG.15, and FIG. 17. The low voltage current transformers 113 can beinstalled on both the incoming breaker connections 118 e and theoutgoing breaker connections 118 d by mounting the low voltage currenttransformers 113 on the mounting block assemblies 104. In an embodiment,multiple current transformers 113 can be accommodated on each of themounting block assemblies 104.

FIGS. 22A-22B exemplarily illustrate perspective views of a controlpower transformer 119 comprising fuse sleeve assemblies 119 a utilizedin the front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700. The control power transformer 119 iselectrically connected in, for example, the middle compartment 102 bdefined in the electrical enclosure 101 as exemplarily illustrated inFIG. 2, FIG. 5, FIG. 12, FIG. 14B, and FIG. 18A. The control powertransformer 119 is used in the front accessible switchgear assembly 100and the multi-access switchgear assembly 1700 to provide low voltagecontrol power to the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 and building emergency orauxiliary power.

The fuse sleeve assemblies 119 a successfully pass 95000V lightningimpulse tests for a 15000V front accessible switchgear assembly 100 anda 15000V multi-access switchgear assembly 1700 and other voltageswitchgear assemblies. The front accessible switchgear assembly 100 andthe multi-access switchgear assembly 1700 disclosed herein furthercomprise epoxy coated bus bars 103 with a small phase-to-phase distance,for example, 3 inch spacing, between the phases to pass the lightningimpulse test. The fuse sleeve assemblies 119 a are mounted on anenclosure 119 c of the control power transformer 119. The enclosure 119c of the control power transformer 119 is made of a polycarbonate resinthermoplastic material, for example, Lexan® of Saudi Basic IndustriesCorp. The enclosure 119 c of the control power transformer 119 isattached to a metal barrier 119 g. Each control power transformer 119has two fuse sleeve assemblies 119 a. The fuse sleeve assemblies 119 aare operably connected to the control power transformer 119 and allowhigh voltage primary connections of the control power transformer 119 inthe electrical enclosure 101, for example, via the mounting blockassembly 104. Each of the fuse sleeve assemblies 119 a contacts thecylindrical bus 104 c that runs inside each of the mounting legs 104 aof the mounting block assembly 104. Each of the fuse sleeve assemblies119 a is attached to the Lexan enclosure 119 c of the control powertransformer 119.

Each of the fuse sleeve assemblies 119 a of the control powertransformer 119 comprises an internal fuse clip 119 b and a fuse 119 jas exemplarily illustrated in FIG. 22C. The fuse sleeve assemblies 119 aattached to the control power transformer 119 are connected through therear of the middle compartment 102 b and mounted in the mounting blockassembly 104 as exemplarily illustrated in FIG. 2, FIG. 5, FIG. 12, andFIG. 18A. Fuse connections are made from the fuse sleeve assemblies 119a of the control power transformer 119 to the cylindrical bus 104 c thatruns inside each of the mounting legs 104 a of the mounting blockassembly 104 as exemplarily illustrated in FIG. 22E. The mounting blockassembly 104 for mounting the control power transformer 119 does nothave a mounting block cover 104 d and the current transformer 113mounting capability as exemplarily illustrated in FIGS. 22D-22E.

The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein are configured to insulatefuses 119 j, as exemplarily illustrated in FIG. 22C, that connect to thecontrol power transformer 119. The insulated fuses 119 j are enclosed inthe epoxy fuse sleeve assemblies 119 a that are mounted on the Lexanenclosure 119 c of the control power transformer 119. Each of the fusesleeve assemblies 119 a is glued to the epoxy at the ends of the Lexanenclosure 119 c. Each of the fuse clips 119 b of the fuse sleeveassemblies 119 a makes contact with the cylindrical bus 104 c inside themounting block assembly 104 as exemplarily illustrated in FIG. 22E. Inthis embodiment, the mounting block assembly 104 is a single mountingblock assembly 104 since there are no current transformers 113 to bemounted. The other end of each of the fuses 119 j of the fuse sleeveassemblies 119 a has a mating built-in fuse clip and a short cable,which goes through a hole in the Lexan enclosure 119 c to make aconnection to a high voltage terminal of the control power transformer119 at either end. The cylindrical bus 104 c inside the mounting blockassembly 104 is machined such that the cylindrical bus 104 c has aconcave curvature so that each of the fuse sleeve assemblies 119 a ofthe control power transformer 119 makes good contact when the controlpower transformer 119 is racked in during normal operation. The controlpower transformer 119 is mounted on a truck 119 e with rollers 119 fthat roll on a track (not shown) positioned in the middle compartment102 b defined in the electrical enclosure 101 as exemplarily illustratedin FIG. 2, FIG. 5, FIG. 12, FIG. 14B, and FIG. 18A, for racking thecontrol power transformer 119 in and out of the middle compartment 102b. A racking tool (not shown) may be inserted into a circular opening119 i provided on the truck 119 e of the control power transformer 119for racking the control power transformer 119 in and out of the middlecompartment 102 b. The handles 119 h on the truck 119 e of the controlpower transformer 119 are used to remove the control power transformer119 from the track (not shown) in the middle compartment 102 b.

The control power transformer 119 requires only two phases namely phaseA and phase C to power the control power transformer 119. The twophases, namely, phase A and phase C connect to external high voltage busbars 103 via the fuse clips 119 b. The Lexan enclosure 119 c provides aninsulating barrier between the high voltage control power transformerterminals and the chassis of the front accessible switchgear assembly100 and the multi-access switchgear assembly 1700 that are at groundpotential. Each of the fuse sleeve assemblies 119 a provides aninsulating barrier between the high voltage fuse connections and thechassis of the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700. Each of the fuse sleeveassemblies 119 a also encloses the fuse clip 119 b so that energizedhigh voltage components are not exposed. Moreover, the mounting blockassembly 104 provides isolation between the phases of the control powertransformer 119. Furthermore, the curvature of the cylindrical bus 104 cinside the mounting block assembly 104 keeps each fuse clip 119 b insideeach of the fuse sleeve assemblies 119 a to prevent exposure of activeor energized components at any time.

The control power transformer 119 comprises low voltage contacts 119 din the front of the control power transformer 119 as exemplarilyillustrated in FIG. 22A, FIG. 22C, and FIG. 22E. The low voltagecontacts 119 d are configured to disengage from low voltage connectionswithin the electrical enclosure 101 for preventing an event of arcing.The entire control power transformer 119 is designed such that the lowvoltage contacts 119 d disengage before disengagement of the highvoltage contacts for safety. Moreover, the secondary connections canhave either a low voltage breaker mounted on the front or a fuse pullout in the low voltage compartment 107 to safely disconnect the lowvoltage connections before racking the control power transformer 119 outof the middle compartment 102 b. If the low voltage connection, forexample, the control power transformer load, is not disconnected, thereis a possibility of creating an arcing event when the control powertransformer 119 is racked out since primary connections are at 15000V.Hence, the front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein provide additional safetyfeatures.

FIG. 22C exemplarily illustrates a perspective view of the control powertransformer 119, showing an exploded view of one of the fuse sleeveassemblies 119 a operably connected to the control power transformer119. Each of the fuse sleeve assemblies 119 a comprises the fuse 119 jand the fuse clip 119 b. The fuse clip 119 b holds the fuse 119 j withinthe fuse sleeve assemblies 119 a and is in electrical communication withthe cylindrical bus 104 c inside the mounting block assembly 104 asexemplarily illustrated in FIG. 22E, when the control power transformer119 is racked in the middle compartment 102 b during normal operation.

FIG. 22D exemplarily illustrates a plan view showing connection of thecontrol power transformer 119 to the mounting block assembly 104. Eachof the fuse sleeve assemblies 119 a comprising the fuse 119 j and thefuse clip 119 b electrically contacts the cylindrical bus 104 c of themounting block assembly 104 as exemplarily illustrated in FIG. 22E, whenthe control power transformer 119 is racked into the middle compartment102 b defined in the electrical enclosure 101 as exemplarily illustratedin FIG. 2, FIG. 5, FIG. 12, and FIG. 18A. The mounting block assembly104 is configured to accommodate each of the fuse sleeve assemblies 119a and isolate phases of the control power transformer 119.

FIG. 22E exemplarily illustrates a sectional view taken at section B-Bof FIG. 22D, showing connection of the control power transformer 119 toa cylindrical bus 104 c that runs inside the mounting block assembly104. Each of the fuse sleeve assemblies 119 a of the control powertransformer 119 encloses the fuse 119 j and the fuse clip 119 b. Thecontrol power transformer 119 is mounted on a truck 119 e with rollers119 f that roll on a track (not shown) positioned in the middlecompartment 102 b, for racking the control power transformer 119 in andout of the middle compartment 102 b as exemplarily illustrated in FIG.2, FIG. 5, FIG. 12, FIG. 14B, and FIG. 18A. In an embodiment, when thecontrol power transformer 119 is racked in, the fuse clip 119 b of eachof the fuse sleeve assemblies 119 a comes in contact with thecylindrical bus 104 c of the mounting block assembly 104. Thecylindrical bus 104 c is attached to a copper bracket 104 f in themounting block assembly 104 via a fastener 104 g such as a bolt. Thecopper bracket 104 f electrically communicates with one or more of thebus bars 103, for example, the upper horizontal bus bars 103 a via highvoltage electrical cables (not shown). The fuse clip 119 b thereforecontacts the concave cylindrical bus 104 c of the mounting blockassembly 104. The contact between the fuse clip 119 b and thecylindrical bus 104 c provides electrical communication between thecontrol power transformer 119 and the mounting block assembly 104. In anembodiment, the fuse sleeve assemblies 119 a operably connected to thecontrol power transformer 119 contact one or more of the bus bars 103,for example, in the rear compartments 102 e within the electricalenclosure 101 via the mounting block assembly 104.

FIGS. 23A-23B exemplarily illustrate perspective views of an epoxyencapsulated potential transformer 120 utilized in the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700.The epoxy encapsulated potential transformer 120 is an instrumenttransformer used for metering and protection in high-voltage circuits.The epoxy encapsulated potential transformer 120 is designed to presentnegligible load to a power supply being measured and to have a precisevoltage ratio to accurately step down high voltages so that metering andprotective relay equipment can be operated at a lower potential. Thepotential transformer 120 is a designed and encapsulated in, forexample, epoxy. The epoxy encapsulated potential transformer 120 isaccommodated and electrically connected in, for example, the middlecompartment 102 b, or the front lower compartment 102 c defined in theelectrical enclosure 101 as exemplarily illustrated in FIG. 2, FIG. 3,FIG. 5, FIG. 12, FIG. 14B, FIG. 17, and FIG. 18A. The epoxy encapsulatedpotential transformer 120 may be mounted in the front lower compartment102 c as exemplarily illustrated in FIG. 2, FIG. 3, FIG. 5, FIG. 12,FIG. 14B, FIG. 17, and FIG. 18A, or in the middle compartment 102 b toprovide a low footprint. As exemplarily illustrated in FIG. 2, FIG. 3,FIG. 5, FIG. 12, FIG. 14B, FIG. 17, and FIG. 18A, the epoxy encapsulatedpotential transformer 120 is electrically connected in the front lowercompartment 102 c defined in the electrical enclosure 101. In anembodiment, one or more fuse sleeve assemblies 120 a are electricallyconnected to the epoxy encapsulated potential transformer 120.

The potential transformer 120 is epoxy encapsulated and enclosed in anenclosure 120 c made of sheet metal since the epoxy provides adequateinsulation for a lightning impulse of 95000 volts. The compact epoxyencapsulated potential transformer 120 makes connection to the bus bars103 via a single mounting block assembly 104 like the control powertransformer 119. The mounting block assembly 104 for mounting the epoxyencapsulated potential transformer 120 does not have a mounting blockcover 104 d as exemplarily illustrated in FIGS. 23D-23E. The mountingblock assembly 104 for each of the control power transformer 119 and theepoxy encapsulated potential transformer 120 is configured to completelyaccommodate each of the fuse sleeve assemblies 119 a and 120 a of eachof the control power transformer 119 and the epoxy encapsulatedpotential transformer 120 respectively as exemplarily illustrated inFIG. 22D and FIG. 23D respectively. The control power transformer 119and the epoxy encapsulated potential transformer 120 are electricallyconnected in the compartments, for example, the middle compartment 102 band the front lower compartment 102 c respectively defined in theelectrical enclosure 101 via the mounting block assembly 104 asexemplarily illustrated in FIG. 2, FIG. 5, FIG. 12, FIG. 17, and FIG.18A. The mounting block assembly 104 for each of the control powertransformer 119 and the epoxy encapsulated potential transformer 120 isgeometrically the same to ensure that the fuse sleeve assemblies 119 aand 120 a of each of the control power transformer 119 and the epoxyencapsulated potential transformer 120 respectively are captured insidethe mounting block assembly 104. The control power transformer 119 hastwo fuse sleeve assemblies 119 a, for example, phase A and phase C,while the epoxy encapsulated potential transformer 120 has three fusesleeve assemblies 120 a, for example, phase A, phase B, and phase C. Noconnection is made in the middle phase B of the control powertransformer 119.

Each of the fuse sleeve assemblies 120 a of the epoxy encapsulatedpotential transformer 120 comprises an internal fuse clip 120 b and afuse 120 i as exemplarily illustrated in FIG. 23C. The fuse sleeveassemblies 120 a attached to the epoxy encapsulated potentialtransformer 120 are connected through the rear of the front lowercompartment 102 c as exemplarily illustrated in FIG. 12. Fuseconnections are made from the fuse sleeve assemblies 120 a of the epoxyencapsulated potential transformer 120 to the cylindrical bus 104 cmounted in the mounting block assembly 104 as exemplarily illustrated inFIG. 23E.

The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein are configured to insulatefuses 120 i that connect to the epoxy encapsulated potential transformer120. The insulated fuses 120 i, exemplarily illustrated in FIG. 23C, areenclosed in the epoxy fuse sleeve assemblies 120 a that are mounted onthe epoxy encapsulated potential transformer 120, which is mounted onthe truck 120 d and enclosed by the sheet metal enclosure 120 c. Each ofthe fuse clips 120 b of the fuse sleeve assemblies 120 a makes contactwith the cylindrical bus 104 c that runs inside each of the mountinglegs 104 a of the mounting block assembly 104 as exemplarily illustratedin FIG. 23E. In this embodiment, the mounting block assembly 104 is asingle mounting block assembly 104 since there are no currenttransformers 113 to be mounted. The epoxy encapsulated potentialtransformer 120 is enclosed in, for example, a sheet metal enclosure 120c, and the fuse sleeve assemblies 120 a are a part of the epoxyencapsulated potential transformer 120. The other end of each of thefuses 120 i of the fuse sleeve assemblies 120 a has a mating built-infuse clip inside the fuse sleeve assembly 120 a and a short cableinternally connected to a high voltage winding of the epoxy encapsulatedpotential transformer 120 within the epoxy enclosure. The potentialtransformer 120 is encapsulated in epoxy and the supporting structure ofthe epoxy encapsulated potential transformer 120 can be made of, forexample, a sheet metal.

The above arrangement is for a wye or star connected potentialtransformer 120 that has three phases and requires three fuse sleeveassemblies 120 a for a wye or star connected supply system with aneutral connection. In an embodiment, two epoxy encapsulated potentialtransformers 120 may also be employed with three fuse sleeve assemblies120 a in an open delta configuration for ungrounded delta connectedsupply systems (not shown) to prevent damage of the epoxy encapsulatedpotential transformers 120 in the event of a ground fault by the flow ofzero sequence currents. In the open delta configuration, two epoxyencapsulated potential transformers 120 are used and a plexi-glassshield is mounted on top of the two epoxy encapsulated potentialtransformers 120 to mount the three fuse sleeve assemblies 120 a. Thefuse sleeve assemblies 120 a are glued to the plexi-glass shield orsheet on top of the two epoxy encapsulated potential transformers 120 oneither side, connected to phases A and B and phases B and C of the epoxyencapsulated potential transformers 120. The high voltage common pointis connected to the middle B fuse while the other two fuses 120 i areconnected to phases A and C.

The cylindrical bus 104 c that runs inside the mounting block assembly104 is machined such that the cylindrical bus 104 c has a concavecurvature so that each of the fuse sleeve assemblies 120 a makes goodcontact when the epoxy encapsulated potential transformer 120 is rackedin during normal operation. The epoxy encapsulated potential transformer120 is mounted on a truck 120 d that has rollers 120 e which roll on atrack (not shown) positioned in the middle compartment 102 b or thelower compartment 102 c defined in the electrical enclosure 101 asexemplarily illustrated in FIG. 2, FIG. 5, FIG. 12, FIG. 17, and FIG.18A, for racking the epoxy encapsulated potential transformer 120 in andout of the middle compartment 102 b or the lower compartment 102 c. Aracking tool (not shown) may be inserted into a circular opening 120 hprovided on the truck 120 d of the epoxy encapsulated potentialtransformer 120 for racking the epoxy encapsulated potential transformer120 in and out of the middle compartment 102 b or the lower compartment102 c. The handles 120 g on the truck 120 d of the epoxy encapsulatedpotential transformer 120 are used to remove the epoxy encapsulatedpotential transformer 120 from the track (not shown) in the middlecompartment 102 b or the lower compartment 102 c.

The epoxy encapsulated potential transformer 120 has three connectionsnamely phase A, phase B, and phase C as opposed to the two phases,namely the phase A and the phase C of the control power transformer 119.The epoxy encapsulated potential transformer 120 is designed and testedto withstand a 95000V lightning impulse and has been independentlytested to meet Institution of Electrical and Electronics Engineers(IEEE) standards and American National Standards Institute (ANSI)standards for instrument transformers which is much more stringent thanthe IEC standards. The height of the epoxy encapsulated potentialtransformer 120 is small making it possible to install the epoxyencapsulated potential transformer 120 in the lower compartment 102 c.When the epoxy encapsulated potential transformer 120 is installed inthe lower compartment 102 c, the lower compartment 102 c is separatedfrom the rear compartment 102 e with a barrier 101 e, which makes thelower compartment 102 c small as exemplarily illustrated in FIG. 12. Thelower compartment 102 c that accommodates the epoxy encapsulatedpotential transformer 120 poses challenges to efficiently vent gases inthe event of an arcing. The design and venting of the gases of the frontaccessible switchgear assembly 100 and the multi-access switchgearassembly 1700 are efficient and has been fully tested to IEEE/ANSIstandards. The low voltage contacts 120 f of the epoxy encapsulatedpotential transformer 120 are designed similar to the low voltagecontacts 119 d of the control power transformer 119 and have the sameadvantages and functionalities.

The epoxy encapsulated potential transformer 120 comprises low voltagecontacts 120 f in the front of the epoxy encapsulated potentialtransformer 120. The low voltage contacts 120 f are configured todisengage from low voltage connections within the electrical enclosure101 for preventing an event of arcing. The entire epoxy encapsulatedpotential transformer 120 is designed such that the low voltage contacts120 f disengage before disengagement of the high voltage contacts forsafety. Moreover, the secondary connections can have either a lowvoltage breaker on the sheet metal enclosure 120 c or a fuse pull out inthe low voltage compartment 107 to safely disconnect the low voltageconnections before racking the epoxy encapsulated potential transformer120 out of, for example, the lower compartment 102 c. If the low voltageconnection, for example, the epoxy encapsulated potential transformerload, is not disconnected, there is a possibility of creating an arcingevent when the epoxy encapsulated potential transformer 120 is rackedout since primary connections are at 15000V. Hence, the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700disclosed herein provides additional safety features.

The epoxy encapsulated potential transformer load is small and does nottypically require a breaker or a fuse pull out to safely disconnect thesecondary low voltage loads before the epoxy encapsulated potentialtransformer 120 is racked out. However, in an embodiment, a secondarybreaker or a fuse pull out similar to that of a control powertransformer 119 is incorporated in each of the front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700.

FIG. 23C exemplarily illustrates a perspective view of the epoxyencapsulated potential transformer 120, showing an exploded view of oneof the fuse sleeve assemblies 120 a operably connected to the epoxyencapsulated potential transformer 120. Each of the fuse sleeveassemblies 120 a of the epoxy encapsulated potential transformer 120comprises the fuse 120 i and the fuse clip 120 b. The fuse clip 120 bholds the fuse 120 i within each of the fuse sleeve assemblies 120 a andis in electrical communication with the cylindrical bus 104 c inside themounting block assembly 104 as exemplarily illustrated in FIG. 23E, whenthe epoxy encapsulated potential transformer 120 is racked in the lowercompartment 102 c as exemplarily illustrated in FIG. 2, FIG. 5, FIG. 12,FIG. 14B, FIG. 17, and FIG. 18A. Each of the fuse sleeve assemblies 120a of the epoxy encapsulated potential transformer 120 allows highvoltage primary connections of the epoxy encapsulated potentialtransformer 120 in the electrical enclosure 101 via the mounting blockassembly 104 as exemplarily illustrated in FIG. 12, FIG. 17, and FIG.18A. Each of the fuse sleeve assemblies 120 a contacts the cylindricalbus 104 c that runs inside each of the mounting legs 104 a of themounting block assembly 104 as exemplarily illustrated in FIG. 23E.

FIG. 23D exemplarily illustrates a plan view showing connection of theepoxy encapsulated potential transformer 120 to the mounting blockassembly 104. Each of the fuse sleeve assemblies 120 a comprising thefuse 120 i and the fuse clip 120 b, as exemplarily illustrated in FIG.23C, electrically contacts the cylindrical bus 104 c of the mountingblock assembly 104 as exemplarily illustrated in FIG. 23E, when theepoxy encapsulated potential transformer 120 is racked into the lowercompartment 102 c defined in the electrical enclosure 101 as exemplarilyillustrated in FIG. 12, FIG. 17, and FIG. 18A. The mounting blockassembly 104 is configured to accommodate each of the fuse sleeveassemblies 120 a and isolate phases of the epoxy encapsulated potentialtransformer 120.

FIG. 23E exemplarily illustrates a sectional view taken at section C-Cof FIG. 23D, showing connection of the epoxy encapsulated potentialtransformer 120 to a cylindrical bus 104 c that runs inside the mountingblock assembly 104. Each of the fuse sleeve assemblies 120 a of theepoxy encapsulated potential transformer 120 encloses the fuse 120 i andthe fuse clip 120 b. The epoxy encapsulated potential transformer 120 ismounted on a truck 120 d with rollers 120 e, which facilitates themounting of the epoxy encapsulated potential transformer 120 on a track(not shown) in the middle compartment 102 b, or the lower compartment102 c as exemplarily illustrated in FIG. 2, FIG. 5, FIG. 12, FIG. 14B,FIG. 17, and FIG. 18A. The epoxy encapsulated potential transformer 120can be racked in and out of the middle compartment 102 b or the lowercompartment 102 c. In an embodiment, when the epoxy encapsulatedpotential transformer 120 is racked in, the fuse clip 120 b of each ofthe fuse sleeve assemblies 120 a comes in electrical contact with thecylindrical bus 104 c of the mounting block assembly 104. Thecylindrical bus 104 c is attached to a copper bracket 104 f in themounting block assembly 104 via a fastener 104 g such as a bolt. Thecopper bracket 104 f electrically communicates with one or more of thebus bars 103, for example, the upper horizontal bus bars 103 a via highvoltage electrical cables (not shown). The fuse clip 120 b thereforecontacts the concave cylindrical bus 104 c of the mounting blockassembly 104. The contact between the fuse clip 120 b and thecylindrical bus 104 c provides electrical communication between theepoxy encapsulated potential transformer 120 and the mounting blockassembly 104. In an embodiment, the fuse sleeve assemblies 120 aoperably connected to the epoxy encapsulated potential transformer 120contact one or more of the bus bars 103, for example, in the rearcompartments 102 e within the electrical enclosure 101 via the mountingblock assembly 104.

FIG. 24 illustrates a method for constructing a front accessibleswitchgear assembly 100. An electrical enclosure 101, for example, witha width of 23.62 inches, a depth of 60 inches, and height of 96 inchesis provided 2401. The electrical enclosure 101 comprises multiplecompartments 102, for example, upper compartments 102 a, middlecompartments 102 b, lower compartments 102 c, a central compartment 102d, rear compartments 102 e, etc., defined in sections, for example, afirst section 101 a and a second section 101 b of the electricalenclosure 101, as exemplarily illustrated in FIGS. 1A-1B and FIGS.2-16D. The compartments 102 are configured to interchangeablyaccommodate one or more electrical components, for example, the controlequipment, the circuit breaker 118, the control power transformer 119,the epoxy encapsulated potential transformer 120, the electrical cables111, etc., and the bus bars 103, for example, the upper horizontal busbars 103 a, the lower horizontal bus bars 103 d, the cable connectionbus bars 103 c, and the transitional bus bars 103 b, as exemplarilyillustrated in FIGS. 1A-1B, FIGS. 2-5, and FIGS. 11A-16D. One or more ofthe compartments 102 a, 102 c, etc., are configured 2402 for enablingthe electrical cables 111 to enter into and/or exit out from theelectrical enclosure 101 for allowing only front access to theelectrical cables 111. A mounting block assembly 104, as exemplarilyillustrated in FIG. 20C, is positioned 2403 in one or more of thecompartments 102, for example, 102 b, 102 d, etc., for providing frontaccess to one or more of the electrical components 113, 118, 119, 120,etc., mounted in the mounting block assembly 104.

One or more the electrical components 113, 118, 119, 120, etc., and theelectrical cables 111 are mounted and electrically connected 2404 inpredetermined positions in the compartments 102 and/or the mountingblock assembly 104 for allowing front access to the electricalcomponents 113, 118, 119, 120, etc., the electrical cables 111, and thebus bars 103 within the electrical enclosure 101. For example, thecircuit breaker 118, as exemplarily illustrated in FIGS. 21A-21B, iselectrically connected in the middle compartment 102 b defined in thefirst section 101 a of the electrical enclosure 101 as exemplarilyillustrated in FIG. 1B, FIG. 4A, FIG. 11A, and FIG. 15. The electricalcables 111 are accommodated and electrically connected in the frontlower compartment 102 c defined in the first section 101 a of theelectrical enclosure 101 as exemplarily illustrated in FIGS. 1A-1B, FIG.3, FIGS. 4A-4B, FIG. 10, FIGS. 11A-11B, and FIG. 13. In an embodiment,the electrical cables 111 enter into and/or exit out from the electricalenclosure 101 via the upper compartment 102 a as exemplarily illustratedin FIGS. 16A-16D.

The control power transformer 119, as exemplarily illustrated in FIGS.22A-22C, is electrically connected in the middle compartment 102 bdefined in the second section 101 b of the electrical enclosure 101 asexemplarily illustrated in FIG. 2, FIG. 5, FIG. 12, and FIG. 14B. Theepoxy encapsulated potential transformer 120, as exemplarily illustratedin FIGS. 23A-23C, is electrically connected in the front lowercompartment 102 c defined in the second section 101 b of the electricalenclosure 101 as exemplarily illustrated in FIG. 2, FIG. 3, FIG. 5, FIG.12, and FIG. 14B. The plenum chamber 105 is rearwardly positioned in thefirst section 101 a of the electrical enclosure 101 and is in adjacentcommunication with the exhaust chamber 112 as exemplarily illustrated inFIGS. 1A-1B, FIGS. 3-7, FIGS. 9-10, FIGS. 11A-11B, and FIGS. 12-13. Oneor more of the electrical components 113, 118, 119, 120, etc., and theelectrical cables 111 are in electrical communication with one or moreof the bus bars 103 in one or more of the compartments 102. One or moreinfrared windows 108 and inspection windows 109 are positioned atpredetermined locations on the front side 100 a of the front accessibleswitchgear assembly 100 for front scanning the electrical components113, 118, 119, 120, etc., and the bus bars 103 in the compartments 102and for providing a front visual indication of the electrical components118, 119, 120, etc., and the bus bars 103 respectively for inspectionand maintenance as exemplarily illustrated in FIGS. 1A-1B, FIG. 2, FIG.4B, FIG. 6, FIG. 8, FIG. 16B, and FIG. 16D.

FIG. 25 illustrates a method for constructing a multi-access switchgearassembly 1700. An electrical enclosure 101, for example, with a width of23.62 inches, a depth of 72 inches, and a height of 96 inches isprovided 2501. In an embodiment, the width of the electrical enclosure101 of the multi-access switchgear assembly 1700 may be reduced. Theelectrical enclosure 101 comprises multiple compartments 102, forexample, upper compartments 102 a, middle compartments 102 b, lowercompartments 102 c, a central compartment 102 d, rear compartments 102e, etc., defined in sections, for example, a first section 101 a and asecond section 101 b, as exemplarily illustrated in FIGS. 1A-1B, FIGS.2-16D, and FIGS. 17-19B. The compartments 102 are configured tointerchangeably accommodate one or more electrical components, forexample, the control equipment, the circuit breaker 118, the controlpower transformer 119, the epoxy encapsulated potential transformer 120,the electrical cables 111, etc., and the bus bars 103, for example, theupper horizontal bus bars 103 a, the lower horizontal bus bars 103 d,the cable connection bus bars 103 c, and the transitional bus bars 103b, as exemplarily illustrated in FIG. 17, FIG. 18A, and FIG. 19A. One ormore of the compartments, for example, 102 a, 102 c, 102 e, etc., areconfigured 2502 for enabling the electrical cables 111 to enter intoand/or exit out from the electrical enclosure 101 for allowing frontaccess and/or rear access to the electrical cables 111 as exemplarilyillustrated in FIG. 17, FIG. 18A, and FIG. 19A. A mounting blockassembly 104, as exemplarily illustrated in FIG. 20C, is positioned 2503in one or more of the compartments 102, for example, 102 b, 102 c, etc.,for mounting one or more of the electrical components 113, 118, 119,120, etc., and for providing front access to the electrical components113, 118, 119, 120, etc., mounted in the mounting block assembly 104 forinspection and maintenance.

One or more the electrical components 113, 118, 119, 120, etc., and theelectrical cables 111 are mounted and electrically connected 2504 inpredetermined positions in the compartments 102 and/or the mountingblock assembly 104 for allowing front access and/or rear access to theelectrical components 113, 118, 119, 120, etc., the electrical cables111, and the bus bars 103 within the electrical enclosure 101. One ormore of the electrical components 113, 118, 119, 120, etc., and theelectrical cables 111 are in electrical communication with one or moreof the bus bars 103 in one or more of the compartments 102. In anexample, the circuit breaker 118, as exemplarily illustrated in FIGS.21A-21B, is electrically connected in the middle compartment 102 bdefined in the electrical enclosure 101 as exemplarily illustrated inFIG. 17 and FIG. 19A. The current transformers 113, as exemplarilyillustrated in FIG. 20C, having one of multiple current ratios, aremounted on an input and an output of the circuit breaker 118 via themounting block assembly 104 as exemplarily illustrated in FIG. 17.

The electrical cables 111 are accommodated and electrically connected inthe rear lower compartment 102 e defined in the electrical enclosure 101as exemplarily illustrated in FIG. 17 and FIGS. 18A-18B. In anembodiment, the electrical cables 111 are accommodated and electricallyconnected in the front lower compartment 102 c and the rear lowercompartment 102 e defined in the electrical enclosure 101, asexemplarily illustrated in 19A-19B. In another embodiment, theelectrical cables 111 enter into and/or exit out from the electricalenclosure 101 via the upper compartment 102 a as exemplarily illustratedin FIGS. 16A-16D. The compartments, for example, 102 a, 102 c, 102 e,etc., of the multi-access switchgear assembly 1700 therefore providefront access and/or rear access to the electrical cables 111.

The control power transformer 119, as exemplarily illustrated in FIGS.22A-22C, having one of multiple power ratings, is electrically connectedin the middle compartment 102 b defined in the electrical enclosure 101as exemplarily illustrated in FIG. 18A. The epoxy encapsulated potentialtransformer 120, as exemplarily illustrated in FIGS. 23A-23C, having oneof multiple voltage levels, is electrically connected, for example, inthe front lower compartment 102 c defined in the electrical enclosure101 as exemplarily illustrated in FIG. 17 and FIG. 18A. The plenumchamber 105 is rearwardly positioned in the electrical enclosure 101 andis in adjacent communication with the exhaust chamber 112 as disclosedin the detailed description of FIG. 17 and as exemplarily illustrated inFIGS. 17-19B. In an embodiment, flaps 106 a, 106 b, and 106 c arepositioned between one or more of the compartments 102 and the plenumchamber 105 for isolating one or more of the compartments 102 from theplenum chamber 105 and for preventing gases and external particulatematter from entering the compartments 102 via the plenum chamber 105.

One or more of the electrical components 113, 118, 119, 120, etc., andthe electrical cables 111 are in electrical communication with one ormore of the bus bars 103 in one or more of the compartments 102. One ormore infrared windows 108 and inspection windows 109 are positioned atpredetermined locations on the front side 1700 a and/or the rear side1700 b of the multi-access switchgear assembly 1700 for front scanningand/or rear scanning the electrical components 113, 118, 119, 120, etc.,the electrical cables 111, and the bus bars 103 in the compartments 102and for providing a front visual indication and/or a rear visualindication of the electrical components 118, 119, 120, etc., theelectrical cables 111, and the bus bars 103 respectively for inspectionand maintenance as exemplarily illustrated in FIG. 17, FIG. 18A, andFIG. 19A. In an embodiment, insulating barriers are provided betweenhigh voltage primary connections and the electrical enclosure 101 of themulti-access switchgear assembly 1700 for preventing exposure of activeelectrical components 119, 120, etc., within the electrical enclosure101.

The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein can be adapted to flexibleconfigurations to form a family of small footprint switchgear assemblies100 and 1700 at medium voltage. The flexible configurations provide asmaller footprint for the switchgear assemblies 100 and 1700 thatrequire arc resistance with front access and/or rear access. The frontaccessible switchgear assembly 100 disclosed herein has full frontaccessibility making the front accessible switchgear assembly 100convenient for applications such as data centers, facilities, industrialapplications with limited space for medium voltage electrical equipment.The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein are configured, for example,for a voltage rating of 15 kV, 95 kV basic impulse level (BIL), acurrent rating of 600 A, 1000 A, and 1200 A, a short circuit and shorttime rating of 31.5 kiloampere (kA), and an arc rating of 25 kA. Acontrol power transformer 119 having up to 15 kVA power is availablewith the front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 disclosed herein.

The front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 successfully completed BIL tests at 95 kV,short circuit tests at 31.5 kA, and temperature tests at 1200 A. Inaddition, all required arc tests were completed at 28 kA at 15.6 kVsuccessfully. The circuit breaker 118 disclosed herein is a magneticallyactuated, vacuum circuit breaker that conforms to ANSI/IEEE standards.The mounting block assembly 104 design, epoxy coated bus bars 103, etc.,make the front accessible switchgear assembly 100 and the multi-accessswitchgear assembly 1700 ultra compact and arc resistant.

Although the front accessible switchgear assembly 100 and themulti-access switchgear assembly 1700 disclosed herein refer to mediumvoltage switchgear assemblies, the front accessible switchgear assembly100 and the multi-access switchgear assembly 1700 disclosed herein maybe extended to a higher voltage switchgear assembly and a lower voltageswitchgear assembly with appropriate modifications. The front accessibleswitchgear assembly 100 and the multi-access switchgear assembly 1700disclosed herein are adapted for 15 kV class equipment, 95 kV lightningimpulse voltage, and 1200 A rating and can be extended to higher ratingsand used for a low voltage switchgear rated 600V and below. In the frontaccessible switchgear assembly 100 and the multi-access switchgearassembly 1700 disclosed herein, low voltage 600V current transformers113 can be used for medium voltage applications at 15000V. This resultsin substantial savings in cost and space requirements.

The foregoing examples have been provided merely for the purpose ofexplanation and are in no way to be construed as limiting of the presentinvention disclosed herein. While the invention has been described withreference to various embodiments, it is understood that the words, whichhave been used herein, are words of description and illustration, ratherthan words of limitation. Further, although the invention has beendescribed herein with reference to particular means, materials andembodiments, the invention is not intended to be limited to theparticulars disclosed herein; rather, the invention extends to allfunctionally equivalent structures, methods and uses, such as are withinthe scope of the appended claims. Those skilled in the art, having thebenefit of the teachings of this specification, may affect numerousmodifications thereto and changes may be made without departing from thescope and spirit of the invention in its aspects.

We claim:
 1. A multi-access switchgear assembly, comprising: a pluralityof compartments defined within an electrical enclosure, wherein saidcompartments are configured to interchangeably accommodate one or moreelectrical components, electrical cables, and bus bars; one or more ofsaid compartments configured for enabling said electrical cables toenter into and/or exit out from said electrical enclosure for allowingfront access and/or rear access to said electrical cables; a mountingblock assembly positioned in one or more of said compartments formounting one or more of said electrical components and for providingfront access to said mounted one or more electrical components forinspection and maintenance, wherein said mounting block assembly furthercomprises: a plurality of mounting legs extending frontwardly from abase mounting block for mounting said one or more of said electricalcomponents and for allowing said front access to said mounted one ormore electrical components; and a mounting block cover removablyattached to said base mounting block for enclosing said mounted one ormore electrical components on said mounting legs, wherein said mountingblock cover is removable for providing said front access to said mountedone or more electrical components for said inspection and saidmaintenance; said one or more electrical components and said electricalcables electrically connected in predetermined positions in saidcompartments for allowing said front access and/or rear access to saidone or more electrical components, said electrical cables, and said busbars within said electrical enclosure, wherein one or more of said oneor more electrical components and said electrical cables are inelectrical communication with one or more of said bus bars in one ormore of said compartments.
 2. The multi-access switchgear assembly ofclaim 1, wherein said mounting block assembly is configured to reducetemperature rise in said compartments.
 3. The multi-access switchgearassembly of claim 1, further comprising one or more infrared windowspositioned at predetermined locations on one or more of a front side anda rear side of said multi-access switchgear assembly for front scanningand/or rear scanning of said one or more electrical components, saidelectrical cables, and said bus bars in said compartments for saidinspection and said maintenance.
 4. The multi-access switchgear assemblyof claim 1, further comprising one or more inspection windows positionedat predetermined locations on one or more of a front side and a rearside of said multi-access switchgear assembly for providing a frontvisual indication and/or a rear visual indication of said one or moreelectrical components, said electrical cables, and said bus bars in saidcompartments for said inspection and said maintenance.
 5. Themulti-access switchgear assembly of claim 1, further comprising a plenumchamber rearwardly positioned in said electrical enclosure, wherein saidplenum chamber is in communication with one or more of said compartmentsand provides an exit path for releasing pressure and gases generated bysaid one or more electrical components and said electrical cablesaccommodated in said one or more of said compartments during an event ofarcing within said electrical enclosure.
 6. The multi-access switchgearassembly of claim 5, further comprising flaps positioned between saidcompartments and said plenum chamber for preventing said gases andexternal particulate matter from entering said compartments via saidplenum chamber.
 7. The multi-access switchgear assembly of claim 5,wherein said plenum chamber communicates with one or more of saidcompartments via an exhaust chamber in adjacent communication with saidplenum chamber.
 8. The multi-access switchgear assembly of claim 1,wherein one or more of said compartments is configured as a low voltagecompartment for accommodating control equipment, wherein said lowvoltage compartment is isolated from a plenum chamber rearwardlypositioned in said electrical enclosure and other of said compartments.9. A multi-access switchgear assembly, comprising: a plurality ofcompartments defined within an electrical enclosure, wherein saidcompartments are configured to interchangeably accommodate one or moreelectrical components, electrical cables, and bus bars; one or more ofsaid compartments configured for enabling said electrical cables toenter into and/or exit out from said electrical enclosure for allowingfront access and/or rear access to said electrical cables, wherein oneof said one or more electrical components is a control power transformerhaving one of a plurality of power ratings electrically connected in amiddle one of said compartments; a mounting block assembly positioned inone or more of said compartments for mounting one or more of saidelectrical components and for providing front access to said mounted oneor more electrical components for inspection and maintenance; one ormore fuse sleeve assemblies operably connected to said control powertransformer, wherein said one or more fuse sleeve assemblies allow highvoltage primary connections of said control power transformer in saidelectrical enclosure, wherein said one or more fuse sleeve assembliesoperably connected to said control power transformer contact one or moreof said bus bars in a rear one of said compartments within saidelectrical enclosure via said mounting block assembly, wherein saidmounting block assembly is configured to accommodate each of said one ormore fuse sleeve assemblies and isolate phases of said control powertransformer; and said one or more electrical components and saidelectrical cables electrically connected in predetermined positions insaid compartments for allowing said front access and/or rear access tosaid one or more electrical components, said electrical cables, and saidbus bars within said electrical enclosure, wherein one or more of saidone or more electrical components and said electrical cables are inelectrical communication with one or more of said bus bars in one ormore of said compartments.
 10. The multi-access switchgear assembly ofclaim 9, wherein said control power transformer comprises low voltagecontacts configured to disengage from low voltage connections withinsaid electrical enclosure for preventing an event of arcing.
 11. Themulti-access switchgear assembly of claim 1, wherein one of said one ormore electrical components is a current transformer having one of aplurality of current ratios mounted in said mounting block assembly inone of said compartments.
 12. The multi-access switchgear assembly ofclaim 1, wherein one of said one or more electrical components is acircuit breaker electrically connected in a middle one of saidcompartments.
 13. The multi-access switchgear assembly of claim 12,further comprising a cord electrically connected to said circuit breakerfor low voltage connection within said electrical enclosure.
 14. Themulti-access switchgear assembly of claim 12, wherein another of saidone or more electrical components are current transformers having one ofa plurality of current ratios, mounted on an input of said circuitbreaker and an output of said circuit breaker via said mounting blockassembly.
 15. A multi-access switchgear assembly, comprising: aplurality of compartments defined within an electrical enclosure,wherein said compartments are configured to interchangeably accommodateone or more electrical components, electrical cables, and bus bars,wherein one of said one or more electrical components is an epoxyencapsulated potential transformer having one of a plurality of voltagelevels accommodated and electrical connected in one of a middle one ofsaid compartments and a lower one of said compartments; one or more ofsaid compartments configured for enabling said electrical cables toenter into and/or exit out from said electrical enclosure for allowingfront access and/or rear access to said electrical cables; a mountingblock assembly positioned in one or more of said compartments formounting one or more of said electrical components and for providingfront access to said mounted one or more electrical components forinspection and maintenance; and one or more fuse sleeve assembliesoperably connected to said epoxy encapsulated potential transformer,wherein said one or more fuse sleeve assemblies allow high voltageprimary connections of said epoxy encapsulated potential transformer insaid electrical enclosure, wherein said one or more fuse sleeveassemblies operably connected to said epoxy encapsulated potentialtransformer contact one or more of said bus bars in a rear one of saidcompartments within said electrical enclosure via said mounting blockassembly, and wherein said mounting block assembly is configured toaccommodate each of said one or more fuse sleeve assemblies and isolatephases of said epoxy encapsulated potential transformer; said one ormore electrical components and said electrical cables electricallyconnected in predetermined positions in said compartments for allowingsaid front access and/or rear access to said one or more electricalcomponents, said electrical cables, and said bus bars within saidelectrical enclosure, and wherein one or more of said one or moreelectrical components and said electrical cables are in electricalcommunication with one or more of said bus bars in one or more of saidcompartments.
 16. The multi-access switchgear assembly of claim 15,wherein said epoxy encapsulated potential transformer comprises lowvoltage contacts configured to disengage from low voltage connectionswithin said electrical enclosure for preventing an event of arcing. 17.The multi-access switchgear assembly of claim 1, wherein said electricalcables enter into and/or exit out from said electrical enclosure via oneor more of an upper one of said compartments, a front one of lower ofsaid compartments, and a rear one of said lower of said compartments.18. The multi-access switchgear assembly of claim 1, wherein said busbars are electrically connected in a rear one of said compartmentswithin said electrical enclosure.
 19. The multi-access switchgearassembly of claim 1 being a metal clad switchgear assembly, whereinadjacent sections defined in said electrical enclosure of said metalclad switchgear assembly are separated by vertical metal barriers forcompartmentalizing active electrical components in said electricalenclosure.
 20. The multi-access switchgear assembly of claim 1, whereinsaid bus bars comprise horizontal bus bars electrically connected in arear one of said compartments within said electrical enclosure, whereinone or more of said horizontal bus bars allow connection to adjacentsections defined in said electrical enclosure, connection between saidone or more electrical components in said adjacent sections defined insaid electrical enclosure, connection between said electrical cables inadjacent said compartments in said electrical enclosure and in saidadjacent sections defined in said electrical enclosure, and connectionto one or more other switchgear assemblies.
 21. The multi-accessswitchgear assembly of claim 1, further comprising surge arresterspositioned in a rear one of said compartments for protecting saidelectrical components, said bus bars, inspection windows, infraredwindows, said electrical cables, said mounting block assembly, and saidcompartments defined within said electrical enclosure in an event of alightning surge, wherein said surge arresters are electrically connectedto one or more of said bus bars in said electrical enclosure via highvoltage electrical cables.
 22. A multi-access switchgear assembly,comprising: a plurality of compartments defined within an electricalenclosure, wherein said compartments are configured to interchangeablyaccommodate a circuit breaker, current transformers having one or moreof a plurality of current ratios, a control power transformer having oneof a plurality of power ratings, an epoxy encapsulated potentialtransformer having one of a plurality of voltage levels, electricalcables, and bus bars; one or more of an upper one of said compartments,a front one of lower of said compartments, and a rear one of said lowerof said compartments configured for enabling said electrical cables toenter into and/or exit out from said electrical enclosure for allowingfront access and/or rear access to said electrical cables; one or moreof said bus bars in electrical communication with one or more of saidelectrical cables, said circuit breaker, said control power transformer,and said epoxy encapsulated potential transformer in one or more of saidcompartments; a low voltage compartment configured in one of an upperone of said compartments, a middle one of said compartments, and a lowerone of said compartments, wherein said low voltage compartment isisolated from other said compartments; a mounting block assemblypositioned in one or more of said compartments for mounting each of saidcurrent transformers, said circuit breaker, said control powertransformer, and said epoxy encapsulated potential transformer, whereinsaid mounting block assembly provides front access to said mountedcurrent transformers, said circuit breaker, said control powertransformer, and said epoxy encapsulated potential transformer forinspection and maintenance; said circuit breaker mounted in a middle oneof said compartments in one of at least two sections of said electricalenclosure and electrically connected within said mounting blockassembly, wherein said circuit breaker contacts one or more of said busbars via said mounting block assembly; one or more fuse sleeveassemblies operably connected to each of said control power transformerand said epoxy encapsulated potential transformer allowing high voltageprimary connections in said electrical enclosure, wherein said one ormore fuse sleeve assemblies provide insulating barriers between saidhigh voltage primary connections and said electrical enclosure; saidcurrent transformers mounted in said mounting block assembly and adaptedfor saving space in said electrical enclosure; said control powertransformer mounted and electrically connected in a middle one of saidcompartments in another one of said at least two sections of saidelectrical enclosure; and said epoxy encapsulated potential transformermounted and electrically connected in one of a lower one of saidcompartments and a middle one of said compartments in another one ofsaid at least two sections of said electrical enclosure; whereby saidepoxy encapsulated potential transformer, said electrical cables, andone of said circuit breaker and said control power transformer arepositioned in a single one of said at least two sections of saidmulti-access switchgear assembly.
 23. The multi-access switchgearassembly of claim 22, further comprising a plenum chamber rearwardlypositioned in said electrical enclosure and in adjacent communicationwith an exhaust chamber for providing an exit path for releasingpressure and gases generated by said circuit breaker, said currenttransformers, said control power transformer, said epoxy encapsulatedpotential transformer, and said electrical cables accommodated in saidcompartments during an event of arcing within said electrical enclosure.24. The multi-access switchgear assembly of claim 22, wherein saidcontrol power transformer and said epoxy encapsulated potentialtransformer are electrically connected in one or more of saidcompartments via said mounting block assembly.
 25. The multi-accessswitchgear assembly of claim 22 configured to line up with a switchgearhaving a current rating of about 2000 amperes, thereby enabling usage ofsaid circuit breaker having a current rating of about 1200 amperes and2000 amperes.
 26. A method for constructing a multi-access switchgearassembly, comprising: providing an electrical enclosure comprising aplurality of compartments, wherein said compartments are configured tointerchangeably accommodate one or more electrical components,electrical cables, and bus bars; configuring one or more of saidcompartments for enabling said electrical cables to enter into and/orexit out from said electrical enclosure for allowing front access and/orrear access to said electrical cables; positioning a mounting blockassembly in one or more of said compartments for mounting one or more ofsaid electrical components and for providing front access to saidmounted one or more electrical components for inspection andmaintenance, wherein said mounting block assembly further comprises: aplurality of mounting legs extending frontwardly from a base mountingblock for mounting said one or more of said electrical components andfor allowing said front access to said mounted one or more electricalcomponents; and a mounting block cover removably attached to said basemounting block for enclosing said mounted one or more electricalcomponents on said mounting legs, wherein said mounting block cover isremovable for providing said front access to said mounted one or moreelectrical components for said inspection and said maintenance; mountingand electrically connecting said one or more electrical components andsaid electrical cables in predetermined positions in said compartmentsand said mounting block assembly for allowing said front access and/orrear access to said one or more electrical components, said electricalcables, and said bus bars within said electrical enclosure, wherein oneor more of said one or more electrical components and said electricalcables are in electrical communication with one or more of said bus barsin one or more of said compartments.
 27. The method of claim 26, furthercomprising rearwardly positioning a plenum chamber in said electricalenclosure, wherein said plenum chamber is in communication with one ormore of said compartments and in adjacent communication with an exhaustchamber for providing an exit path for releasing pressure and gasesgenerated by said one or more electrical components and said electricalcables accommodated in said one or more of said compartments during anevent of arcing within said electrical enclosure.
 28. The method ofclaim 27, further comprising isolating one or more of said compartmentsand said plenum chamber by one or more flaps positioned between said oneor more compartments and said plenum chamber for preventing said gasesand external particulate matter from entering said one or morecompartments via said plenum chamber.
 29. The method of claim 26,further comprising providing insulating barriers between high voltageprimary connections and said electrical enclosure of said multi-accessswitchgear assembly for preventing exposure of active electricalcomponents within said electrical enclosure.